* [PATCH v6 bpf-next 01/14] bpf: fix bpf_put_raw_tracepoint()'s use of __module_address()
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 02/14] bpf: keep module's btf_data_size intact after load Andrii Nakryiko
` (12 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team, Martin KaFai Lau
__module_address() needs to be called with preemption disabled or with
module_mutex taken. preempt_disable() is enough for read-only uses, which is
what this fix does. Also, module_put() does internal check for NULL, so drop
it as well.
Fixes: a38d1107f937 ("bpf: support raw tracepoints in modules")
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/trace/bpf_trace.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d255bc9b2bfa..23a390aac524 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2060,10 +2060,12 @@ struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name)
void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
{
- struct module *mod = __module_address((unsigned long)btp);
+ struct module *mod;
- if (mod)
- module_put(mod);
+ preempt_disable();
+ mod = __module_address((unsigned long)btp);
+ module_put(mod);
+ preempt_enable();
}
static __always_inline
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 02/14] bpf: keep module's btf_data_size intact after load
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 01/14] bpf: fix bpf_put_raw_tracepoint()'s use of __module_address() Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 03/14] libbpf: add internal helper to load BTF data by FD Andrii Nakryiko
` (11 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Having real btf_data_size stored in struct module is benefitial to quickly
determine which kernel modules have associated BTF object and which don't.
There is no harm in keeping this info, as opposed to keeping invalid pointer.
Fixes: 607c543f939d ("bpf: Sanitize BTF data pointer after module is loaded")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/module.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/kernel/module.c b/kernel/module.c
index 18f259d61d14..c3a9e972d3b2 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3712,7 +3712,6 @@ static noinline int do_init_module(struct module *mod)
#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
/* .BTF is not SHF_ALLOC and will get removed, so sanitize pointer */
mod->btf_data = NULL;
- mod->btf_data_size = 0;
#endif
/*
* We want to free module_init, but be aware that kallsyms may be
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 03/14] libbpf: add internal helper to load BTF data by FD
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 01/14] bpf: fix bpf_put_raw_tracepoint()'s use of __module_address() Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 02/14] bpf: keep module's btf_data_size intact after load Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 04/14] libbpf: refactor CO-RE relocs to not assume a single BTF object Andrii Nakryiko
` (10 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Add a btf_get_from_fd() helper, which constructs struct btf from in-kernel BTF
data by FD. This is used for loading module BTFs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/btf.c | 61 +++++++++++++++++++--------------
tools/lib/bpf/libbpf_internal.h | 1 +
2 files changed, 36 insertions(+), 26 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 1935e83d309c..3c3f2bc6c652 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1323,35 +1323,27 @@ const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
return btf__str_by_offset(btf, offset);
}
-int btf__get_from_id(__u32 id, struct btf **btf)
+struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf)
{
- struct bpf_btf_info btf_info = { 0 };
+ struct bpf_btf_info btf_info;
__u32 len = sizeof(btf_info);
__u32 last_size;
- int btf_fd;
+ struct btf *btf;
void *ptr;
int err;
- err = 0;
- *btf = NULL;
- btf_fd = bpf_btf_get_fd_by_id(id);
- if (btf_fd < 0)
- return 0;
-
/* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
* let's start with a sane default - 4KiB here - and resize it only if
* bpf_obj_get_info_by_fd() needs a bigger buffer.
*/
- btf_info.btf_size = 4096;
- last_size = btf_info.btf_size;
+ last_size = 4096;
ptr = malloc(last_size);
- if (!ptr) {
- err = -ENOMEM;
- goto exit_free;
- }
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
- memset(ptr, 0, last_size);
+ memset(&btf_info, 0, sizeof(btf_info));
btf_info.btf = ptr_to_u64(ptr);
+ btf_info.btf_size = last_size;
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
if (!err && btf_info.btf_size > last_size) {
@@ -1360,31 +1352,48 @@ int btf__get_from_id(__u32 id, struct btf **btf)
last_size = btf_info.btf_size;
temp_ptr = realloc(ptr, last_size);
if (!temp_ptr) {
- err = -ENOMEM;
+ btf = ERR_PTR(-ENOMEM);
goto exit_free;
}
ptr = temp_ptr;
- memset(ptr, 0, last_size);
+
+ len = sizeof(btf_info);
+ memset(&btf_info, 0, sizeof(btf_info));
btf_info.btf = ptr_to_u64(ptr);
+ btf_info.btf_size = last_size;
+
err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
}
if (err || btf_info.btf_size > last_size) {
- err = errno;
+ btf = err ? ERR_PTR(-errno) : ERR_PTR(-E2BIG);
goto exit_free;
}
- *btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size);
- if (IS_ERR(*btf)) {
- err = PTR_ERR(*btf);
- *btf = NULL;
- }
+ btf = btf_new(ptr, btf_info.btf_size, base_btf);
exit_free:
- close(btf_fd);
free(ptr);
+ return btf;
+}
- return err;
+int btf__get_from_id(__u32 id, struct btf **btf)
+{
+ struct btf *res;
+ int btf_fd;
+
+ *btf = NULL;
+ btf_fd = bpf_btf_get_fd_by_id(id);
+ if (btf_fd < 0)
+ return -errno;
+
+ res = btf_get_from_fd(btf_fd, NULL);
+ close(btf_fd);
+ if (IS_ERR(res))
+ return PTR_ERR(res);
+
+ *btf = res;
+ return 0;
}
int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index d99bc847bf84..e569ae63808e 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -155,6 +155,7 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size);
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off);
+struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
struct btf_ext_info {
/*
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 04/14] libbpf: refactor CO-RE relocs to not assume a single BTF object
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (2 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 03/14] libbpf: add internal helper to load BTF data by FD Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 05/14] libbpf: add kernel module BTF support for CO-RE relocations Andrii Nakryiko
` (9 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team, Martin KaFai Lau
Refactor CO-RE relocation candidate search to not expect a single BTF, rather
return all candidate types with their corresponding BTF objects. This will
allow to extend CO-RE relocations to accommodate kernel module BTFs.
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/libbpf.c | 187 ++++++++++++++++++++++++-----------------
1 file changed, 111 insertions(+), 76 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b2e16efabde0..2e4fa3ce6b94 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -462,11 +462,14 @@ struct bpf_object {
struct list_head list;
struct btf *btf;
+ struct btf_ext *btf_ext;
+
/* Parse and load BTF vmlinux if any of the programs in the object need
* it at load time.
*/
struct btf *btf_vmlinux;
- struct btf_ext *btf_ext;
+ /* vmlinux BTF override for CO-RE relocations */
+ struct btf *btf_vmlinux_override;
void *priv;
bpf_object_clear_priv_t clear_priv;
@@ -4600,46 +4603,43 @@ static size_t bpf_core_essential_name_len(const char *name)
return n;
}
-/* dynamically sized list of type IDs */
-struct ids_vec {
- __u32 *data;
+struct core_cand
+{
+ const struct btf *btf;
+ const struct btf_type *t;
+ const char *name;
+ __u32 id;
+};
+
+/* dynamically sized list of type IDs and its associated struct btf */
+struct core_cand_list {
+ struct core_cand *cands;
int len;
};
-static void bpf_core_free_cands(struct ids_vec *cand_ids)
+static void bpf_core_free_cands(struct core_cand_list *cands)
{
- free(cand_ids->data);
- free(cand_ids);
+ free(cands->cands);
+ free(cands);
}
-static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
- __u32 local_type_id,
- const struct btf *targ_btf)
+static int bpf_core_add_cands(struct core_cand *local_cand,
+ size_t local_essent_len,
+ const struct btf *targ_btf,
+ const char *targ_btf_name,
+ int targ_start_id,
+ struct core_cand_list *cands)
{
- size_t local_essent_len, targ_essent_len;
- const char *local_name, *targ_name;
- const struct btf_type *t, *local_t;
- struct ids_vec *cand_ids;
- __u32 *new_ids;
- int i, err, n;
-
- local_t = btf__type_by_id(local_btf, local_type_id);
- if (!local_t)
- return ERR_PTR(-EINVAL);
-
- local_name = btf__name_by_offset(local_btf, local_t->name_off);
- if (str_is_empty(local_name))
- return ERR_PTR(-EINVAL);
- local_essent_len = bpf_core_essential_name_len(local_name);
-
- cand_ids = calloc(1, sizeof(*cand_ids));
- if (!cand_ids)
- return ERR_PTR(-ENOMEM);
+ struct core_cand *new_cands, *cand;
+ const struct btf_type *t;
+ const char *targ_name;
+ size_t targ_essent_len;
+ int n, i;
n = btf__get_nr_types(targ_btf);
- for (i = 1; i <= n; i++) {
+ for (i = targ_start_id; i <= n; i++) {
t = btf__type_by_id(targ_btf, i);
- if (btf_kind(t) != btf_kind(local_t))
+ if (btf_kind(t) != btf_kind(local_cand->t))
continue;
targ_name = btf__name_by_offset(targ_btf, t->name_off);
@@ -4650,25 +4650,62 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
if (targ_essent_len != local_essent_len)
continue;
- if (strncmp(local_name, targ_name, local_essent_len) == 0) {
- pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s\n",
- local_type_id, btf_kind_str(local_t),
- local_name, i, btf_kind_str(t), targ_name);
- new_ids = libbpf_reallocarray(cand_ids->data,
- cand_ids->len + 1,
- sizeof(*cand_ids->data));
- if (!new_ids) {
- err = -ENOMEM;
- goto err_out;
- }
- cand_ids->data = new_ids;
- cand_ids->data[cand_ids->len++] = i;
- }
+ if (strncmp(local_cand->name, targ_name, local_essent_len) != 0)
+ continue;
+
+ pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s in [%s]\n",
+ local_cand->id, btf_kind_str(local_cand->t),
+ local_cand->name, i, btf_kind_str(t), targ_name,
+ targ_btf_name);
+ new_cands = libbpf_reallocarray(cands->cands, cands->len + 1,
+ sizeof(*cands->cands));
+ if (!new_cands)
+ return -ENOMEM;
+
+ cand = &new_cands[cands->len];
+ cand->btf = targ_btf;
+ cand->t = t;
+ cand->name = targ_name;
+ cand->id = i;
+
+ cands->cands = new_cands;
+ cands->len++;
}
- return cand_ids;
-err_out:
- bpf_core_free_cands(cand_ids);
- return ERR_PTR(err);
+ return 0;
+}
+
+static struct core_cand_list *
+bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
+{
+ struct core_cand local_cand = {};
+ struct core_cand_list *cands;
+ size_t local_essent_len;
+ int err;
+
+ local_cand.btf = local_btf;
+ local_cand.t = btf__type_by_id(local_btf, local_type_id);
+ if (!local_cand.t)
+ return ERR_PTR(-EINVAL);
+
+ local_cand.name = btf__name_by_offset(local_btf, local_cand.t->name_off);
+ if (str_is_empty(local_cand.name))
+ return ERR_PTR(-EINVAL);
+ local_essent_len = bpf_core_essential_name_len(local_cand.name);
+
+ cands = calloc(1, sizeof(*cands));
+ if (!cands)
+ return ERR_PTR(-ENOMEM);
+
+ /* Attempt to find target candidates in vmlinux BTF first */
+ err = bpf_core_add_cands(&local_cand, local_essent_len,
+ obj->btf_vmlinux_override ?: obj->btf_vmlinux,
+ "vmlinux", 1, cands);
+ if (err) {
+ bpf_core_free_cands(cands);
+ return ERR_PTR(err);
+ }
+
+ return cands;
}
/* Check two types for compatibility for the purpose of field access
@@ -5661,7 +5698,6 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
const struct bpf_core_relo *relo,
int relo_idx,
const struct btf *local_btf,
- const struct btf *targ_btf,
struct hashmap *cand_cache)
{
struct bpf_core_spec local_spec, cand_spec, targ_spec = {};
@@ -5669,8 +5705,8 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
struct bpf_core_relo_res cand_res, targ_res;
const struct btf_type *local_type;
const char *local_name;
- struct ids_vec *cand_ids;
- __u32 local_id, cand_id;
+ struct core_cand_list *cands = NULL;
+ __u32 local_id;
const char *spec_str;
int i, j, err;
@@ -5717,24 +5753,24 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
return -EOPNOTSUPP;
}
- if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
- cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
- if (IS_ERR(cand_ids)) {
+ if (!hashmap__find(cand_cache, type_key, (void **)&cands)) {
+ cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
+ if (IS_ERR(cands)) {
pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld",
prog->name, relo_idx, local_id, btf_kind_str(local_type),
- local_name, PTR_ERR(cand_ids));
- return PTR_ERR(cand_ids);
+ local_name, PTR_ERR(cands));
+ return PTR_ERR(cands);
}
- err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
+ err = hashmap__set(cand_cache, type_key, cands, NULL, NULL);
if (err) {
- bpf_core_free_cands(cand_ids);
+ bpf_core_free_cands(cands);
return err;
}
}
- for (i = 0, j = 0; i < cand_ids->len; i++) {
- cand_id = cand_ids->data[i];
- err = bpf_core_spec_match(&local_spec, targ_btf, cand_id, &cand_spec);
+ for (i = 0, j = 0; i < cands->len; i++) {
+ err = bpf_core_spec_match(&local_spec, cands->cands[i].btf,
+ cands->cands[i].id, &cand_spec);
if (err < 0) {
pr_warn("prog '%s': relo #%d: error matching candidate #%d ",
prog->name, relo_idx, i);
@@ -5778,7 +5814,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
return -EINVAL;
}
- cand_ids->data[j++] = cand_spec.root_type_id;
+ cands->cands[j++] = cands->cands[i];
}
/*
@@ -5790,7 +5826,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
* depending on relo's kind.
*/
if (j > 0)
- cand_ids->len = j;
+ cands->len = j;
/*
* If no candidates were found, it might be both a programmer error,
@@ -5834,20 +5870,19 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
struct hashmap_entry *entry;
struct hashmap *cand_cache = NULL;
struct bpf_program *prog;
- struct btf *targ_btf;
const char *sec_name;
int i, err = 0, insn_idx, sec_idx;
if (obj->btf_ext->core_relo_info.len == 0)
return 0;
- if (targ_btf_path)
- targ_btf = btf__parse(targ_btf_path, NULL);
- else
- targ_btf = obj->btf_vmlinux;
- if (IS_ERR_OR_NULL(targ_btf)) {
- pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf));
- return PTR_ERR(targ_btf);
+ if (targ_btf_path) {
+ obj->btf_vmlinux_override = btf__parse(targ_btf_path, NULL);
+ if (IS_ERR_OR_NULL(obj->btf_vmlinux_override)) {
+ err = PTR_ERR(obj->btf_vmlinux_override);
+ pr_warn("failed to parse target BTF: %d\n", err);
+ return err;
+ }
}
cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
@@ -5899,8 +5934,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
if (!prog->load)
continue;
- err = bpf_core_apply_relo(prog, rec, i, obj->btf,
- targ_btf, cand_cache);
+ err = bpf_core_apply_relo(prog, rec, i, obj->btf, cand_cache);
if (err) {
pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
prog->name, i, err);
@@ -5911,8 +5945,9 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
out:
/* obj->btf_vmlinux is freed at the end of object load phase */
- if (targ_btf != obj->btf_vmlinux)
- btf__free(targ_btf);
+ btf__free(obj->btf_vmlinux_override);
+ obj->btf_vmlinux_override = NULL;
+
if (!IS_ERR_OR_NULL(cand_cache)) {
hashmap__for_each_entry(cand_cache, entry, i) {
bpf_core_free_cands(entry->value);
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 05/14] libbpf: add kernel module BTF support for CO-RE relocations
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (3 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 04/14] libbpf: refactor CO-RE relocs to not assume a single BTF object Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 06/14] selftests/bpf: add bpf_testmod kernel module for testing Andrii Nakryiko
` (8 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Teach libbpf to search for candidate types for CO-RE relocations across kernel
modules BTFs, in addition to vmlinux BTF. If at least one candidate type is
found in vmlinux BTF, kernel module BTFs are not iterated. If vmlinux BTF has
no matching candidates, then find all kernel module BTFs and search for all
matching candidates across all of them.
Kernel's support for module BTFs are inferred from the support for BTF name
pointer in BPF UAPI.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/libbpf.c | 179 ++++++++++++++++++++++++++++++++++++++---
1 file changed, 169 insertions(+), 10 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2e4fa3ce6b94..ca20e493726d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -176,6 +176,8 @@ enum kern_feature_id {
FEAT_PROBE_READ_KERN,
/* BPF_PROG_BIND_MAP is supported */
FEAT_PROG_BIND_MAP,
+ /* Kernel support for module BTFs */
+ FEAT_MODULE_BTF,
__FEAT_CNT,
};
@@ -402,6 +404,12 @@ struct extern_desc {
static LIST_HEAD(bpf_objects_list);
+struct module_btf {
+ struct btf *btf;
+ char *name;
+ __u32 id;
+};
+
struct bpf_object {
char name[BPF_OBJ_NAME_LEN];
char license[64];
@@ -470,6 +478,11 @@ struct bpf_object {
struct btf *btf_vmlinux;
/* vmlinux BTF override for CO-RE relocations */
struct btf *btf_vmlinux_override;
+ /* Lazily initialized kernel module BTFs */
+ struct module_btf *btf_modules;
+ bool btf_modules_loaded;
+ size_t btf_module_cnt;
+ size_t btf_module_cap;
void *priv;
bpf_object_clear_priv_t clear_priv;
@@ -3960,6 +3973,35 @@ static int probe_prog_bind_map(void)
return ret >= 0;
}
+static int probe_module_btf(void)
+{
+ static const char strs[] = "\0int";
+ __u32 types[] = {
+ /* int */
+ BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
+ };
+ struct bpf_btf_info info;
+ __u32 len = sizeof(info);
+ char name[16];
+ int fd, err;
+
+ fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs));
+ if (fd < 0)
+ return 0; /* BTF not supported at all */
+
+ memset(&info, 0, sizeof(info));
+ info.name = ptr_to_u64(name);
+ info.name_len = sizeof(name);
+
+ /* check that BPF_OBJ_GET_INFO_BY_FD supports specifying name pointer;
+ * kernel's module BTF support coincides with support for
+ * name/name_len fields in struct bpf_btf_info.
+ */
+ err = bpf_obj_get_info_by_fd(fd, &info, &len);
+ close(fd);
+ return !err;
+}
+
enum kern_feature_result {
FEAT_UNKNOWN = 0,
FEAT_SUPPORTED = 1,
@@ -4003,7 +4045,10 @@ static struct kern_feature_desc {
},
[FEAT_PROG_BIND_MAP] = {
"BPF_PROG_BIND_MAP support", probe_prog_bind_map,
- }
+ },
+ [FEAT_MODULE_BTF] = {
+ "module BTF support", probe_module_btf,
+ },
};
static bool kernel_supports(enum kern_feature_id feat_id)
@@ -4674,13 +4719,96 @@ static int bpf_core_add_cands(struct core_cand *local_cand,
return 0;
}
+static int load_module_btfs(struct bpf_object *obj)
+{
+ struct bpf_btf_info info;
+ struct module_btf *mod_btf;
+ struct btf *btf;
+ char name[64];
+ __u32 id = 0, len;
+ int err, fd;
+
+ if (obj->btf_modules_loaded)
+ return 0;
+
+ /* don't do this again, even if we find no module BTFs */
+ obj->btf_modules_loaded = true;
+
+ /* kernel too old to support module BTFs */
+ if (!kernel_supports(FEAT_MODULE_BTF))
+ return 0;
+
+ while (true) {
+ err = bpf_btf_get_next_id(id, &id);
+ if (err && errno == ENOENT)
+ return 0;
+ if (err) {
+ err = -errno;
+ pr_warn("failed to iterate BTF objects: %d\n", err);
+ return err;
+ }
+
+ fd = bpf_btf_get_fd_by_id(id);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ continue; /* expected race: BTF was unloaded */
+ err = -errno;
+ pr_warn("failed to get BTF object #%d FD: %d\n", id, err);
+ return err;
+ }
+
+ len = sizeof(info);
+ memset(&info, 0, sizeof(info));
+ info.name = ptr_to_u64(name);
+ info.name_len = sizeof(name);
+
+ err = bpf_obj_get_info_by_fd(fd, &info, &len);
+ if (err) {
+ err = -errno;
+ pr_warn("failed to get BTF object #%d info: %d\n", id, err);
+ close(fd);
+ return err;
+ }
+
+ /* ignore non-module BTFs */
+ if (!info.kernel_btf || strcmp(name, "vmlinux") == 0) {
+ close(fd);
+ continue;
+ }
+
+ btf = btf_get_from_fd(fd, obj->btf_vmlinux);
+ close(fd);
+ if (IS_ERR(btf)) {
+ pr_warn("failed to load module [%s]'s BTF object #%d: %ld\n",
+ name, id, PTR_ERR(btf));
+ return PTR_ERR(btf);
+ }
+
+ err = btf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap,
+ sizeof(*obj->btf_modules), obj->btf_module_cnt + 1);
+ if (err)
+ return err;
+
+ mod_btf = &obj->btf_modules[obj->btf_module_cnt++];
+
+ mod_btf->btf = btf;
+ mod_btf->id = id;
+ mod_btf->name = strdup(name);
+ if (!mod_btf->name)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
static struct core_cand_list *
bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
{
struct core_cand local_cand = {};
struct core_cand_list *cands;
+ const struct btf *main_btf;
size_t local_essent_len;
- int err;
+ int err, i;
local_cand.btf = local_btf;
local_cand.t = btf__type_by_id(local_btf, local_type_id);
@@ -4697,15 +4825,38 @@ bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 l
return ERR_PTR(-ENOMEM);
/* Attempt to find target candidates in vmlinux BTF first */
- err = bpf_core_add_cands(&local_cand, local_essent_len,
- obj->btf_vmlinux_override ?: obj->btf_vmlinux,
- "vmlinux", 1, cands);
- if (err) {
- bpf_core_free_cands(cands);
- return ERR_PTR(err);
+ main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
+ err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
+ if (err)
+ goto err_out;
+
+ /* if vmlinux BTF has any candidate, don't got for module BTFs */
+ if (cands->len)
+ return cands;
+
+ /* if vmlinux BTF was overridden, don't attempt to load module BTFs */
+ if (obj->btf_vmlinux_override)
+ return cands;
+
+ /* now look through module BTFs, trying to still find candidates */
+ err = load_module_btfs(obj);
+ if (err)
+ goto err_out;
+
+ for (i = 0; i < obj->btf_module_cnt; i++) {
+ err = bpf_core_add_cands(&local_cand, local_essent_len,
+ obj->btf_modules[i].btf,
+ obj->btf_modules[i].name,
+ btf__get_nr_types(obj->btf_vmlinux) + 1,
+ cands);
+ if (err)
+ goto err_out;
}
return cands;
+err_out:
+ bpf_core_free_cands(cands);
+ return ERR_PTR(err);
}
/* Check two types for compatibility for the purpose of field access
@@ -5756,7 +5907,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
if (!hashmap__find(cand_cache, type_key, (void **)&cands)) {
cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
if (IS_ERR(cands)) {
- pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld",
+ pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
prog->name, relo_idx, local_id, btf_kind_str(local_type),
local_name, PTR_ERR(cands));
return PTR_ERR(cands);
@@ -5944,7 +6095,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
}
out:
- /* obj->btf_vmlinux is freed at the end of object load phase */
+ /* obj->btf_vmlinux and module BTFs are freed after object load */
btf__free(obj->btf_vmlinux_override);
obj->btf_vmlinux_override = NULL;
@@ -7316,6 +7467,14 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
err = err ? : bpf_object__relocate(obj, attr->target_btf_path);
err = err ? : bpf_object__load_progs(obj, attr->log_level);
+ /* clean up module BTFs */
+ for (i = 0; i < obj->btf_module_cnt; i++) {
+ btf__free(obj->btf_modules[i].btf);
+ free(obj->btf_modules[i].name);
+ }
+ free(obj->btf_modules);
+
+ /* clean up vmlinux BTF */
btf__free(obj->btf_vmlinux);
obj->btf_vmlinux = NULL;
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 06/14] selftests/bpf: add bpf_testmod kernel module for testing
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (4 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 05/14] libbpf: add kernel module BTF support for CO-RE relocations Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 07/14] selftests/bpf: add support for marking sub-tests as skipped Andrii Nakryiko
` (7 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team, Martin KaFai Lau
Add bpf_testmod module, which is conceptually out-of-tree module and provides
ways for selftests/bpf to test various kernel module-related functionality:
raw tracepoint, fentry/fexit/fmod_ret, etc. This module will be auto-loaded by
test_progs test runner and expected by some of selftests to be present and
loaded.
Pahole currently isn't able to generate BTF for static functions in kernel
modules, so make sure traced function is global.
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/testing/selftests/bpf/.gitignore | 1 +
tools/testing/selftests/bpf/Makefile | 12 +++-
.../selftests/bpf/bpf_testmod/.gitignore | 6 ++
.../selftests/bpf/bpf_testmod/Makefile | 20 +++++++
.../bpf/bpf_testmod/bpf_testmod-events.h | 36 +++++++++++
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 52 ++++++++++++++++
.../selftests/bpf/bpf_testmod/bpf_testmod.h | 14 +++++
tools/testing/selftests/bpf/test_progs.c | 59 +++++++++++++++++++
tools/testing/selftests/bpf/test_progs.h | 1 +
9 files changed, 198 insertions(+), 3 deletions(-)
create mode 100644 tools/testing/selftests/bpf/bpf_testmod/.gitignore
create mode 100644 tools/testing/selftests/bpf/bpf_testmod/Makefile
create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h
create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index 395ae040ce1f..752d8edddc66 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -35,3 +35,4 @@ test_cpp
/tools
/runqslower
/bench
+*.ko
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 371b022d932c..ac25ba5d0d6c 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -80,7 +80,7 @@ TEST_PROGS_EXTENDED := with_addr.sh \
# Compile but not part of 'make run_tests'
TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
- test_lirc_mode2_user xdping test_cpp runqslower bench
+ test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko
TEST_CUSTOM_PROGS = urandom_read
@@ -104,6 +104,7 @@ OVERRIDE_TARGETS := 1
override define CLEAN
$(call msg,CLEAN)
$(Q)$(RM) -r $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES) $(EXTRA_CLEAN)
+ $(Q)$(MAKE) -C bpf_testmod clean
endef
include ../lib.mk
@@ -136,6 +137,11 @@ $(OUTPUT)/urandom_read: urandom_read.c
$(call msg,BINARY,,$@)
$(Q)$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS) -Wl,--build-id=sha1
+$(OUTPUT)/bpf_testmod.ko: $(VMLINUX_BTF) $(wildcard bpf_testmod/Makefile bpf_testmod/*.[ch])
+ $(call msg,MOD,,$@)
+ $(Q)$(MAKE) $(submake_extras) -C bpf_testmod
+ $(Q)cp bpf_testmod/bpf_testmod.ko $@
+
$(OUTPUT)/test_stub.o: test_stub.c $(BPFOBJ)
$(call msg,CC,,$@)
$(Q)$(CC) -c $(CFLAGS) -o $@ $<
@@ -388,7 +394,7 @@ TRUNNER_BPF_PROGS_DIR := progs
TRUNNER_EXTRA_SOURCES := test_progs.c cgroup_helpers.c trace_helpers.c \
network_helpers.c testing_helpers.c \
btf_helpers.c flow_dissector_load.h
-TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read \
+TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read $(OUTPUT)/bpf_testmod.ko \
ima_setup.sh \
$(wildcard progs/btf_dump_test_case_*.c)
TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE
@@ -460,4 +466,4 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o $(OUTPUT)/testing_helpers.o \
EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(SCRATCH_DIR) \
prog_tests/tests.h map_tests/tests.h verifier/tests.h \
feature \
- $(addprefix $(OUTPUT)/,*.o *.skel.h no_alu32 bpf_gcc)
+ $(addprefix $(OUTPUT)/,*.o *.skel.h no_alu32 bpf_gcc bpf_testmod.ko)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/.gitignore b/tools/testing/selftests/bpf/bpf_testmod/.gitignore
new file mode 100644
index 000000000000..ded513777281
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_testmod/.gitignore
@@ -0,0 +1,6 @@
+*.mod
+*.mod.c
+*.o
+.ko
+/Module.symvers
+/modules.order
diff --git a/tools/testing/selftests/bpf/bpf_testmod/Makefile b/tools/testing/selftests/bpf/bpf_testmod/Makefile
new file mode 100644
index 000000000000..15cb36c4483a
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_testmod/Makefile
@@ -0,0 +1,20 @@
+BPF_TESTMOD_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
+KDIR ?= $(abspath $(BPF_TESTMOD_DIR)/../../../../..)
+
+ifeq ($(V),1)
+Q =
+else
+Q = @
+endif
+
+MODULES = bpf_testmod.ko
+
+obj-m += bpf_testmod.o
+CFLAGS_bpf_testmod.o = -I$(src)
+
+all:
+ +$(Q)make -C $(KDIR) M=$(BPF_TESTMOD_DIR) modules
+
+clean:
+ +$(Q)make -C $(KDIR) M=$(BPF_TESTMOD_DIR) clean
+
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h
new file mode 100644
index 000000000000..b83ea448bc79
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod-events.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2020 Facebook */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bpf_testmod
+
+#if !defined(_BPF_TESTMOD_EVENTS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _BPF_TESTMOD_EVENTS_H
+
+#include <linux/tracepoint.h>
+#include "bpf_testmod.h"
+
+TRACE_EVENT(bpf_testmod_test_read,
+ TP_PROTO(struct task_struct *task, struct bpf_testmod_test_read_ctx *ctx),
+ TP_ARGS(task, ctx),
+ TP_STRUCT__entry(
+ __field(pid_t, pid)
+ __array(char, comm, TASK_COMM_LEN)
+ __field(loff_t, off)
+ __field(size_t, len)
+ ),
+ TP_fast_assign(
+ __entry->pid = task->pid;
+ memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ __entry->off = ctx->off;
+ __entry->len = ctx->len;
+ ),
+ TP_printk("pid=%d comm=%s off=%llu len=%zu",
+ __entry->pid, __entry->comm, __entry->off, __entry->len)
+);
+
+#endif /* _BPF_TESTMOD_EVENTS_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE bpf_testmod-events
+#include <trace/define_trace.h>
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
new file mode 100644
index 000000000000..2df19d73ca49
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+#include <linux/error-injection.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sysfs.h>
+#include <linux/tracepoint.h>
+#include "bpf_testmod.h"
+
+#define CREATE_TRACE_POINTS
+#include "bpf_testmod-events.h"
+
+noinline ssize_t
+bpf_testmod_test_read(struct file *file, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t len)
+{
+ struct bpf_testmod_test_read_ctx ctx = {
+ .buf = buf,
+ .off = off,
+ .len = len,
+ };
+
+ trace_bpf_testmod_test_read(current, &ctx);
+
+ return -EIO; /* always fail */
+}
+EXPORT_SYMBOL(bpf_testmod_test_read);
+ALLOW_ERROR_INJECTION(bpf_testmod_test_read, ERRNO);
+
+static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = {
+ .attr = { .name = "bpf_testmod", .mode = 0444, },
+ .read = bpf_testmod_test_read,
+};
+
+static int bpf_testmod_init(void)
+{
+ return sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
+}
+
+static void bpf_testmod_exit(void)
+{
+ return sysfs_remove_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file);
+}
+
+module_init(bpf_testmod_init);
+module_exit(bpf_testmod_exit);
+
+MODULE_AUTHOR("Andrii Nakryiko");
+MODULE_DESCRIPTION("BPF selftests module");
+MODULE_LICENSE("Dual BSD/GPL");
+
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
new file mode 100644
index 000000000000..b81adfedb4f6
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2020 Facebook */
+#ifndef _BPF_TESTMOD_H
+#define _BPF_TESTMOD_H
+
+#include <linux/types.h>
+
+struct bpf_testmod_test_read_ctx {
+ char *buf;
+ loff_t off;
+ size_t len;
+};
+
+#endif /* _BPF_TESTMOD_H */
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 22943b58d752..17587754b7a7 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -360,6 +360,58 @@ int extract_build_id(char *build_id, size_t size)
return -1;
}
+static int finit_module(int fd, const char *param_values, int flags)
+{
+ return syscall(__NR_finit_module, fd, param_values, flags);
+}
+
+static int delete_module(const char *name, int flags)
+{
+ return syscall(__NR_delete_module, name, flags);
+}
+
+static void unload_bpf_testmod(void)
+{
+ if (delete_module("bpf_testmod", 0)) {
+ if (errno == ENOENT) {
+ if (env.verbosity > VERBOSE_NONE)
+ fprintf(stdout, "bpf_testmod.ko is already unloaded.\n");
+ return;
+ }
+ fprintf(env.stderr, "Failed to unload bpf_testmod.ko from kernel: %d\n", -errno);
+ exit(1);
+ }
+ if (env.verbosity > VERBOSE_NONE)
+ fprintf(stdout, "Successfully unloaded bpf_testmod.ko.\n");
+}
+
+static int load_bpf_testmod(void)
+{
+ int fd;
+
+ /* ensure previous instance of the module is unloaded */
+ unload_bpf_testmod();
+
+ if (env.verbosity > VERBOSE_NONE)
+ fprintf(stdout, "Loading bpf_testmod.ko...\n");
+
+ fd = open("bpf_testmod.ko", O_RDONLY);
+ if (fd < 0) {
+ fprintf(env.stderr, "Can't find bpf_testmod.ko kernel module: %d\n", -errno);
+ return -ENOENT;
+ }
+ if (finit_module(fd, "", 0)) {
+ fprintf(env.stderr, "Failed to load bpf_testmod.ko into the kernel: %d\n", -errno);
+ close(fd);
+ return -EINVAL;
+ }
+ close(fd);
+
+ if (env.verbosity > VERBOSE_NONE)
+ fprintf(stdout, "Successfully loaded bpf_testmod.ko.\n");
+ return 0;
+}
+
/* extern declarations for test funcs */
#define DEFINE_TEST(name) extern void test_##name(void);
#include <prog_tests/tests.h>
@@ -678,6 +730,11 @@ int main(int argc, char **argv)
save_netns();
stdio_hijack();
+ env.has_testmod = true;
+ if (load_bpf_testmod()) {
+ fprintf(env.stderr, "WARNING! Selftests relying on bpf_testmod.ko will be skipped.\n");
+ env.has_testmod = false;
+ }
for (i = 0; i < prog_test_cnt; i++) {
struct prog_test_def *test = &prog_test_defs[i];
@@ -722,6 +779,8 @@ int main(int argc, char **argv)
if (test->need_cgroup_cleanup)
cleanup_cgroup_environment();
}
+ if (env.has_testmod)
+ unload_bpf_testmod();
stdio_restore();
if (env.get_test_cnt) {
diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
index d6b14853f3bc..115953243f62 100644
--- a/tools/testing/selftests/bpf/test_progs.h
+++ b/tools/testing/selftests/bpf/test_progs.h
@@ -66,6 +66,7 @@ struct test_env {
enum verbosity verbosity;
bool jit_enabled;
+ bool has_testmod;
bool get_test_cnt;
bool list_test_names;
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 07/14] selftests/bpf: add support for marking sub-tests as skipped
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (5 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 06/14] selftests/bpf: add bpf_testmod kernel module for testing Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 08/14] selftests/bpf: add CO-RE relocs selftest relying on kernel module BTF Andrii Nakryiko
` (6 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Previously skipped sub-tests would be counted as passing with ":OK" appened
in the log. Change that to be accounted as ":SKIP".
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/testing/selftests/bpf/test_progs.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 17587754b7a7..5ef081bdae4e 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -149,15 +149,15 @@ void test__end_subtest()
if (sub_error_cnt)
env.fail_cnt++;
- else
+ else if (test->skip_cnt == 0)
env.sub_succ_cnt++;
skip_account();
dump_test_log(test, sub_error_cnt);
fprintf(env.stdout, "#%d/%d %s:%s\n",
- test->test_num, test->subtest_num,
- test->subtest_name, sub_error_cnt ? "FAIL" : "OK");
+ test->test_num, test->subtest_num, test->subtest_name,
+ sub_error_cnt ? "FAIL" : (test->skip_cnt ? "SKIP" : "OK"));
free(test->subtest_name);
test->subtest_name = NULL;
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 08/14] selftests/bpf: add CO-RE relocs selftest relying on kernel module BTF
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (6 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 07/14] selftests/bpf: add support for marking sub-tests as skipped Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 09/14] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier Andrii Nakryiko
` (5 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Add a self-tests validating libbpf is able to perform CO-RE relocations
against the type defined in kernel module BTF. if bpf_testmod.o is not
supported by the kernel (e.g., due to version mismatch), skip tests, instead
of failing.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
.../selftests/bpf/prog_tests/core_reloc.c | 79 ++++++++++++++++---
.../selftests/bpf/progs/core_reloc_types.h | 17 ++++
.../bpf/progs/test_core_reloc_module.c | 66 ++++++++++++++++
3 files changed, 151 insertions(+), 11 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/test_core_reloc_module.c
diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
index 30e40ff4b0d8..bb980848cd77 100644
--- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include "progs/core_reloc_types.h"
+#include "bpf_testmod/bpf_testmod.h"
#include <sys/mman.h>
#include <sys/syscall.h>
#include <bpf/btf.h>
@@ -9,6 +10,30 @@ static int duration = 0;
#define STRUCT_TO_CHAR_PTR(struct_name) (const char *)&(struct struct_name)
+#define MODULES_CASE(name, sec_name, tp_name) { \
+ .case_name = name, \
+ .bpf_obj_file = "test_core_reloc_module.o", \
+ .btf_src_file = NULL, /* find in kernel module BTFs */ \
+ .input = "", \
+ .input_len = 0, \
+ .output = STRUCT_TO_CHAR_PTR(core_reloc_module_output) { \
+ .read_ctx_sz = sizeof(struct bpf_testmod_test_read_ctx),\
+ .read_ctx_exists = true, \
+ .buf_exists = true, \
+ .len_exists = true, \
+ .off_exists = true, \
+ .len = 123, \
+ .off = 0, \
+ .comm = "test_progs", \
+ .comm_len = sizeof("test_progs"), \
+ }, \
+ .output_len = sizeof(struct core_reloc_module_output), \
+ .prog_sec_name = sec_name, \
+ .raw_tp_name = tp_name, \
+ .trigger = trigger_module_test_read, \
+ .needs_testmod = true, \
+}
+
#define FLAVORS_DATA(struct_name) STRUCT_TO_CHAR_PTR(struct_name) { \
.a = 42, \
.b = 0xc001, \
@@ -211,7 +236,7 @@ static int duration = 0;
.output = STRUCT_TO_CHAR_PTR(core_reloc_bitfields_output) \
__VA_ARGS__, \
.output_len = sizeof(struct core_reloc_bitfields_output), \
- .direct_raw_tp = true, \
+ .prog_sec_name = "tp_btf/sys_enter", \
}
@@ -222,7 +247,7 @@ static int duration = 0;
}, { \
BITFIELDS_CASE_COMMON("test_core_reloc_bitfields_direct.o", \
"direct:", name), \
- .direct_raw_tp = true, \
+ .prog_sec_name = "tp_btf/sys_enter", \
.fails = true, \
}
@@ -309,6 +334,7 @@ static int duration = 0;
struct core_reloc_test_case;
typedef int (*setup_test_fn)(struct core_reloc_test_case *test);
+typedef int (*trigger_test_fn)(const struct core_reloc_test_case *test);
struct core_reloc_test_case {
const char *case_name;
@@ -319,9 +345,12 @@ struct core_reloc_test_case {
const char *output;
int output_len;
bool fails;
+ bool needs_testmod;
bool relaxed_core_relocs;
- bool direct_raw_tp;
+ const char *prog_sec_name;
+ const char *raw_tp_name;
setup_test_fn setup;
+ trigger_test_fn trigger;
};
static int find_btf_type(const struct btf *btf, const char *name, __u32 kind)
@@ -451,6 +480,23 @@ static int setup_type_id_case_failure(struct core_reloc_test_case *test)
return 0;
}
+static int trigger_module_test_read(const struct core_reloc_test_case *test)
+{
+ struct core_reloc_module_output *exp = (void *)test->output;
+ int fd, err;
+
+ fd = open("/sys/kernel/bpf_testmod", O_RDONLY);
+ err = -errno;
+ if (CHECK(fd < 0, "testmod_file_open", "failed: %d\n", err))
+ return err;
+
+ read(fd, NULL, exp->len); /* request expected number of bytes */
+ close(fd);
+
+ return 0;
+}
+
+
static struct core_reloc_test_case test_cases[] = {
/* validate we can find kernel image and use its BTF for relocs */
{
@@ -467,6 +513,9 @@ static struct core_reloc_test_case test_cases[] = {
.output_len = sizeof(struct core_reloc_kernel_output),
},
+ /* validate we can find kernel module BTF types for relocs/attach */
+ MODULES_CASE("module", "raw_tp/bpf_testmod_test_read", "bpf_testmod_test_read"),
+
/* validate BPF program can use multiple flavors to match against
* single target BTF type
*/
@@ -779,6 +828,11 @@ void test_core_reloc(void)
if (!test__start_subtest(test_case->case_name))
continue;
+ if (test_case->needs_testmod && !env.has_testmod) {
+ test__skip();
+ continue;
+ }
+
if (test_case->setup) {
err = test_case->setup(test_case);
if (CHECK(err, "test_setup", "test #%d setup failed: %d\n", i, err))
@@ -790,13 +844,11 @@ void test_core_reloc(void)
test_case->bpf_obj_file, PTR_ERR(obj)))
continue;
- /* for typed raw tracepoints, NULL should be specified */
- if (test_case->direct_raw_tp) {
- probe_name = "tp_btf/sys_enter";
- tp_name = NULL;
- } else {
- probe_name = "raw_tracepoint/sys_enter";
- tp_name = "sys_enter";
+ probe_name = "raw_tracepoint/sys_enter";
+ tp_name = "sys_enter";
+ if (test_case->prog_sec_name) {
+ probe_name = test_case->prog_sec_name;
+ tp_name = test_case->raw_tp_name; /* NULL for tp_btf */
}
prog = bpf_object__find_program_by_title(obj, probe_name);
@@ -837,7 +889,12 @@ void test_core_reloc(void)
goto cleanup;
/* trigger test run */
- usleep(1);
+ if (test_case->trigger) {
+ if (!ASSERT_OK(test_case->trigger(test_case), "test_trigger"))
+ goto cleanup;
+ } else {
+ usleep(1);
+ }
if (data->skip) {
test__skip();
diff --git a/tools/testing/selftests/bpf/progs/core_reloc_types.h b/tools/testing/selftests/bpf/progs/core_reloc_types.h
index e6e616cb7bc9..9a2850850121 100644
--- a/tools/testing/selftests/bpf/progs/core_reloc_types.h
+++ b/tools/testing/selftests/bpf/progs/core_reloc_types.h
@@ -15,6 +15,23 @@ struct core_reloc_kernel_output {
int comm_len;
};
+/*
+ * MODULE
+ */
+
+struct core_reloc_module_output {
+ long long len;
+ long long off;
+ int read_ctx_sz;
+ bool read_ctx_exists;
+ bool buf_exists;
+ bool len_exists;
+ bool off_exists;
+ /* we have test_progs[-flavor], so cut flavor part */
+ char comm[sizeof("test_progs")];
+ int comm_len;
+};
+
/*
* FLAVORS
*/
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_module.c b/tools/testing/selftests/bpf/progs/test_core_reloc_module.c
new file mode 100644
index 000000000000..d1840c1a9d36
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_module.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct bpf_testmod_test_read_ctx {
+ /* field order is mixed up */
+ size_t len;
+ char *buf;
+ loff_t off;
+} __attribute__((preserve_access_index));
+
+struct {
+ char in[256];
+ char out[256];
+ bool skip;
+ uint64_t my_pid_tgid;
+} data = {};
+
+struct core_reloc_module_output {
+ long long len;
+ long long off;
+ int read_ctx_sz;
+ bool read_ctx_exists;
+ bool buf_exists;
+ bool len_exists;
+ bool off_exists;
+ /* we have test_progs[-flavor], so cut flavor part */
+ char comm[sizeof("test_progs")];
+ int comm_len;
+};
+
+SEC("raw_tp/bpf_testmod_test_read")
+int BPF_PROG(test_core_module,
+ struct task_struct *task,
+ struct bpf_testmod_test_read_ctx *read_ctx)
+{
+ struct core_reloc_module_output *out = (void *)&data.out;
+ __u64 pid_tgid = bpf_get_current_pid_tgid();
+ __u32 real_tgid = (__u32)(pid_tgid >> 32);
+ __u32 real_pid = (__u32)pid_tgid;
+
+ if (data.my_pid_tgid != pid_tgid)
+ return 0;
+
+ if (BPF_CORE_READ(task, pid) != real_pid || BPF_CORE_READ(task, tgid) != real_tgid)
+ return 0;
+
+ out->len = BPF_CORE_READ(read_ctx, len);
+ out->off = BPF_CORE_READ(read_ctx, off);
+
+ out->read_ctx_sz = bpf_core_type_size(struct bpf_testmod_test_read_ctx);
+ out->read_ctx_exists = bpf_core_type_exists(struct bpf_testmod_test_read_ctx);
+ out->buf_exists = bpf_core_field_exists(read_ctx->buf);
+ out->off_exists = bpf_core_field_exists(read_ctx->off);
+ out->len_exists = bpf_core_field_exists(read_ctx->len);
+
+ out->comm_len = BPF_CORE_READ_STR_INTO(&out->comm, task, comm);
+
+ return 0;
+}
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 09/14] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (7 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 08/14] selftests/bpf: add CO-RE relocs selftest relying on kernel module BTF Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 10/14] bpf: allow to specify kernel module BTFs when attaching BPF programs Andrii Nakryiko
` (4 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Remove a permeating assumption thoughout BPF verifier of vmlinux BTF. Instead,
wherever BTF type IDs are involved, also track the instance of struct btf that
goes along with the type ID. This allows to gradually add support for kernel
module BTFs and using/tracking module types across BPF helper calls and
registers.
This patch also renames btf_id() function to btf_obj_id() to minimize naming
clash with using btf_id to denote BTF *type* ID, rather than BTF *object*'s ID.
Also, altough btf_vmlinux can't get destructed and thus doesn't need
refcounting, module BTFs need that, so apply BTF refcounting universally when
BPF program is using BTF-powered attachment (tp_btf, fentry/fexit, etc). This
makes for simpler clean up code.
Now that BTF type ID is not enough to uniquely identify a BTF type, extend BPF
trampoline key to include BTF object ID. To differentiate that from target
program BPF ID, set 31st bit of type ID. BTF type IDs (at least currently) are
not allowed to take full 32 bits, so there is no danger of confusing that bit
with a valid BTF type ID.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
include/linux/bpf.h | 13 ++++--
include/linux/bpf_verifier.h | 28 +++++++++----
include/linux/btf.h | 5 ++-
kernel/bpf/btf.c | 65 ++++++++++++++++++++----------
kernel/bpf/syscall.c | 24 +++++++++--
kernel/bpf/verifier.c | 77 ++++++++++++++++++++++--------------
net/ipv4/bpf_tcp_ca.c | 3 +-
7 files changed, 148 insertions(+), 67 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a9de5711b23f..d05e75ed8c1b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -421,7 +421,10 @@ struct bpf_insn_access_aux {
enum bpf_reg_type reg_type;
union {
int ctx_field_size;
- u32 btf_id;
+ struct {
+ struct btf *btf;
+ u32 btf_id;
+ };
};
struct bpf_verifier_log *log; /* for verbose logs */
};
@@ -458,6 +461,7 @@ struct bpf_verifier_ops {
struct bpf_insn *dst,
struct bpf_prog *prog, u32 *target_size);
int (*btf_struct_access)(struct bpf_verifier_log *log,
+ const struct btf *btf,
const struct btf_type *t, int off, int size,
enum bpf_access_type atype,
u32 *next_btf_id);
@@ -771,6 +775,7 @@ struct bpf_prog_aux {
u32 ctx_arg_info_size;
u32 max_rdonly_access;
u32 max_rdwr_access;
+ struct btf *attach_btf;
const struct bpf_ctx_arg_aux *ctx_arg_info;
struct mutex dst_mutex; /* protects dst_* pointers below, *after* prog becomes visible */
struct bpf_prog *dst_prog;
@@ -1005,7 +1010,6 @@ struct bpf_event_entry {
bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
int bpf_prog_calc_tag(struct bpf_prog *fp);
-const char *kernel_type_name(u32 btf_type_id);
const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
@@ -1450,12 +1454,13 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
bool btf_ctx_access(int off, int size, enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info);
-int btf_struct_access(struct bpf_verifier_log *log,
+int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
const struct btf_type *t, int off, int size,
enum bpf_access_type atype,
u32 *next_btf_id);
bool btf_struct_ids_match(struct bpf_verifier_log *log,
- int off, u32 id, u32 need_type_id);
+ const struct btf *btf, u32 id, int off,
+ const struct btf *need_btf, u32 need_type_id);
int btf_distill_func_proto(struct bpf_verifier_log *log,
struct btf *btf,
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 306869d4743b..e941fe1484e5 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -5,6 +5,7 @@
#define _LINUX_BPF_VERIFIER_H 1
#include <linux/bpf.h> /* for enum bpf_reg_type */
+#include <linux/btf.h> /* for struct btf and btf_id() */
#include <linux/filter.h> /* for MAX_BPF_STACK */
#include <linux/tnum.h>
@@ -43,6 +44,8 @@ enum bpf_reg_liveness {
struct bpf_reg_state {
/* Ordering of fields matters. See states_equal() */
enum bpf_reg_type type;
+ /* Fixed part of pointer offset, pointer types only */
+ s32 off;
union {
/* valid when type == PTR_TO_PACKET */
int range;
@@ -52,15 +55,20 @@ struct bpf_reg_state {
*/
struct bpf_map *map_ptr;
- u32 btf_id; /* for PTR_TO_BTF_ID */
+ /* for PTR_TO_BTF_ID */
+ struct {
+ struct btf *btf;
+ u32 btf_id;
+ };
u32 mem_size; /* for PTR_TO_MEM | PTR_TO_MEM_OR_NULL */
/* Max size from any of the above. */
- unsigned long raw;
+ struct {
+ unsigned long raw1;
+ unsigned long raw2;
+ } raw;
};
- /* Fixed part of pointer offset, pointer types only */
- s32 off;
/* For PTR_TO_PACKET, used to find other pointers with the same variable
* offset, so they can share range knowledge.
* For PTR_TO_MAP_VALUE_OR_NULL this is used to share which map value we
@@ -311,7 +319,10 @@ struct bpf_insn_aux_data {
struct {
enum bpf_reg_type reg_type; /* type of pseudo_btf_id */
union {
- u32 btf_id; /* btf_id for struct typed var */
+ struct {
+ struct btf *btf;
+ u32 btf_id; /* btf_id for struct typed var */
+ };
u32 mem_size; /* mem_size for non-struct typed var */
};
} btf_var;
@@ -459,9 +470,12 @@ int check_ctx_reg(struct bpf_verifier_env *env,
/* this lives here instead of in bpf.h because it needs to dereference tgt_prog */
static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog,
- u32 btf_id)
+ struct btf *btf, u32 btf_id)
{
- return tgt_prog ? (((u64)tgt_prog->aux->id) << 32 | btf_id) : btf_id;
+ if (tgt_prog)
+ return ((u64)tgt_prog->aux->id << 32) | btf_id;
+ else
+ return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id;
}
int bpf_check_attach_target(struct bpf_verifier_log *log,
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 2bf641829664..fb608e4de076 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -18,6 +18,7 @@ struct btf_show;
extern const struct file_operations btf_fops;
+void btf_get(struct btf *btf);
void btf_put(struct btf *btf);
int btf_new_fd(const union bpf_attr *attr);
struct btf *btf_get_by_fd(int fd);
@@ -88,7 +89,7 @@ int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
char *buf, int len, u64 flags);
int btf_get_fd_by_id(u32 id);
-u32 btf_id(const struct btf *btf);
+u32 btf_obj_id(const struct btf *btf);
bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
const struct btf_member *m,
u32 expected_offset, u32 expected_size);
@@ -206,6 +207,8 @@ static inline const struct btf_var_secinfo *btf_type_var_secinfo(
}
#ifdef CONFIG_BPF_SYSCALL
+struct bpf_prog;
+
const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
const char *btf_name_by_offset(const struct btf *btf, u32 offset);
struct btf *btf_parse_vmlinux(void);
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6b2d508b33d4..7a19bf5bfe97 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -1524,6 +1524,11 @@ static void btf_free_rcu(struct rcu_head *rcu)
btf_free(btf);
}
+void btf_get(struct btf *btf)
+{
+ refcount_inc(&btf->refcnt);
+}
+
void btf_put(struct btf *btf)
{
if (btf && refcount_dec_and_test(&btf->refcnt)) {
@@ -4555,11 +4560,10 @@ struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
{
struct bpf_prog *tgt_prog = prog->aux->dst_prog;
- if (tgt_prog) {
+ if (tgt_prog)
return tgt_prog->aux->btf;
- } else {
- return btf_vmlinux;
- }
+ else
+ return prog->aux->attach_btf;
}
static bool is_string_ptr(struct btf *btf, const struct btf_type *t)
@@ -4700,6 +4704,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
if (ctx_arg_info->offset == off) {
info->reg_type = ctx_arg_info->reg_type;
+ info->btf = btf_vmlinux;
info->btf_id = ctx_arg_info->btf_id;
return true;
}
@@ -4716,6 +4721,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
if (ret > 0) {
+ info->btf = btf_vmlinux;
info->btf_id = ret;
return true;
} else {
@@ -4723,6 +4729,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
}
}
+ info->btf = btf;
info->btf_id = t->type;
t = btf_type_by_id(btf, t->type);
/* skip modifiers */
@@ -4749,7 +4756,7 @@ enum bpf_struct_walk_result {
WALK_STRUCT,
};
-static int btf_struct_walk(struct bpf_verifier_log *log,
+static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
const struct btf_type *t, int off, int size,
u32 *next_btf_id)
{
@@ -4760,7 +4767,7 @@ static int btf_struct_walk(struct bpf_verifier_log *log,
u32 vlen, elem_id, mid;
again:
- tname = __btf_name_by_offset(btf_vmlinux, t->name_off);
+ tname = __btf_name_by_offset(btf, t->name_off);
if (!btf_type_is_struct(t)) {
bpf_log(log, "Type '%s' is not a struct\n", tname);
return -EINVAL;
@@ -4777,7 +4784,7 @@ static int btf_struct_walk(struct bpf_verifier_log *log,
goto error;
member = btf_type_member(t) + vlen - 1;
- mtype = btf_type_skip_modifiers(btf_vmlinux, member->type,
+ mtype = btf_type_skip_modifiers(btf, member->type,
NULL);
if (!btf_type_is_array(mtype))
goto error;
@@ -4793,7 +4800,7 @@ static int btf_struct_walk(struct bpf_verifier_log *log,
/* Only allow structure for now, can be relaxed for
* other types later.
*/
- t = btf_type_skip_modifiers(btf_vmlinux, array_elem->type,
+ t = btf_type_skip_modifiers(btf, array_elem->type,
NULL);
if (!btf_type_is_struct(t))
goto error;
@@ -4851,10 +4858,10 @@ static int btf_struct_walk(struct bpf_verifier_log *log,
/* type of the field */
mid = member->type;
- mtype = btf_type_by_id(btf_vmlinux, member->type);
- mname = __btf_name_by_offset(btf_vmlinux, member->name_off);
+ mtype = btf_type_by_id(btf, member->type);
+ mname = __btf_name_by_offset(btf, member->name_off);
- mtype = __btf_resolve_size(btf_vmlinux, mtype, &msize,
+ mtype = __btf_resolve_size(btf, mtype, &msize,
&elem_type, &elem_id, &total_nelems,
&mid);
if (IS_ERR(mtype)) {
@@ -4949,7 +4956,7 @@ static int btf_struct_walk(struct bpf_verifier_log *log,
mname, moff, tname, off, size);
return -EACCES;
}
- stype = btf_type_skip_modifiers(btf_vmlinux, mtype->type, &id);
+ stype = btf_type_skip_modifiers(btf, mtype->type, &id);
if (btf_type_is_struct(stype)) {
*next_btf_id = id;
return WALK_PTR;
@@ -4975,7 +4982,7 @@ static int btf_struct_walk(struct bpf_verifier_log *log,
return -EINVAL;
}
-int btf_struct_access(struct bpf_verifier_log *log,
+int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
const struct btf_type *t, int off, int size,
enum bpf_access_type atype __maybe_unused,
u32 *next_btf_id)
@@ -4984,7 +4991,7 @@ int btf_struct_access(struct bpf_verifier_log *log,
u32 id;
do {
- err = btf_struct_walk(log, t, off, size, &id);
+ err = btf_struct_walk(log, btf, t, off, size, &id);
switch (err) {
case WALK_PTR:
@@ -5000,7 +5007,7 @@ int btf_struct_access(struct bpf_verifier_log *log,
* by diving in it. At this point the offset is
* aligned with the new type, so set it to 0.
*/
- t = btf_type_by_id(btf_vmlinux, id);
+ t = btf_type_by_id(btf, id);
off = 0;
break;
default:
@@ -5016,21 +5023,37 @@ int btf_struct_access(struct bpf_verifier_log *log,
return -EINVAL;
}
+/* Check that two BTF types, each specified as an BTF object + id, are exactly
+ * the same. Trivial ID check is not enough due to module BTFs, because we can
+ * end up with two different module BTFs, but IDs point to the common type in
+ * vmlinux BTF.
+ */
+static bool btf_types_are_same(const struct btf *btf1, u32 id1,
+ const struct btf *btf2, u32 id2)
+{
+ if (id1 != id2)
+ return false;
+ if (btf1 == btf2)
+ return true;
+ return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
+}
+
bool btf_struct_ids_match(struct bpf_verifier_log *log,
- int off, u32 id, u32 need_type_id)
+ const struct btf *btf, u32 id, int off,
+ const struct btf *need_btf, u32 need_type_id)
{
const struct btf_type *type;
int err;
/* Are we already done? */
- if (need_type_id == id && off == 0)
+ if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
return true;
again:
- type = btf_type_by_id(btf_vmlinux, id);
+ type = btf_type_by_id(btf, id);
if (!type)
return false;
- err = btf_struct_walk(log, type, off, 1, &id);
+ err = btf_struct_walk(log, btf, type, off, 1, &id);
if (err != WALK_STRUCT)
return false;
@@ -5039,7 +5062,7 @@ bool btf_struct_ids_match(struct bpf_verifier_log *log,
* continue the search with offset 0 in the new
* type.
*/
- if (need_type_id != id) {
+ if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
off = 0;
goto again;
}
@@ -5710,7 +5733,7 @@ int btf_get_fd_by_id(u32 id)
return fd;
}
-u32 btf_id(const struct btf *btf)
+u32 btf_obj_id(const struct btf *btf)
{
return btf->id;
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index d16dd4945100..184204169949 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1691,6 +1691,8 @@ static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred)
bpf_prog_kallsyms_del_all(prog);
btf_put(prog->aux->btf);
bpf_prog_free_linfo(prog);
+ if (prog->aux->attach_btf)
+ btf_put(prog->aux->attach_btf);
if (deferred) {
if (prog->aux->sleepable)
@@ -2113,6 +2115,20 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
prog->expected_attach_type = attr->expected_attach_type;
prog->aux->attach_btf_id = attr->attach_btf_id;
+
+ if (attr->attach_btf_id && !attr->attach_prog_fd) {
+ struct btf *btf;
+
+ btf = bpf_get_btf_vmlinux();
+ if (IS_ERR(btf))
+ return PTR_ERR(btf);
+ if (!btf)
+ return -EINVAL;
+
+ btf_get(btf);
+ prog->aux->attach_btf = btf;
+ }
+
if (attr->attach_prog_fd) {
struct bpf_prog *dst_prog;
@@ -2209,6 +2225,8 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
free_uid(prog->aux->user);
security_bpf_prog_free(prog->aux);
free_prog:
+ if (prog->aux->attach_btf)
+ btf_put(prog->aux->attach_btf);
bpf_prog_free(prog);
return err;
}
@@ -2566,7 +2584,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
goto out_put_prog;
}
- key = bpf_trampoline_compute_key(tgt_prog, btf_id);
+ key = bpf_trampoline_compute_key(tgt_prog, NULL, btf_id);
}
link = kzalloc(sizeof(*link), GFP_USER);
@@ -3543,7 +3561,7 @@ static int bpf_prog_get_info_by_fd(struct file *file,
}
if (prog->aux->btf)
- info.btf_id = btf_id(prog->aux->btf);
+ info.btf_id = btf_obj_id(prog->aux->btf);
ulen = info.nr_func_info;
info.nr_func_info = prog->aux->func_info_cnt;
@@ -3646,7 +3664,7 @@ static int bpf_map_get_info_by_fd(struct file *file,
memcpy(info.name, map->name, sizeof(map->name));
if (map->btf) {
- info.btf_id = btf_id(map->btf);
+ info.btf_id = btf_obj_id(map->btf);
info.btf_key_type_id = map->btf_key_type_id;
info.btf_value_type_id = map->btf_value_type_id;
}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e333ce43f281..2f3950839b85 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -238,7 +238,9 @@ struct bpf_call_arg_meta {
u64 msize_max_value;
int ref_obj_id;
int func_id;
+ struct btf *btf;
u32 btf_id;
+ struct btf *ret_btf;
u32 ret_btf_id;
};
@@ -556,10 +558,9 @@ static struct bpf_func_state *func(struct bpf_verifier_env *env,
return cur->frame[reg->frameno];
}
-const char *kernel_type_name(u32 id)
+static const char *kernel_type_name(const struct btf* btf, u32 id)
{
- return btf_name_by_offset(btf_vmlinux,
- btf_type_by_id(btf_vmlinux, id)->name_off);
+ return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off);
}
static void print_verifier_state(struct bpf_verifier_env *env,
@@ -589,7 +590,7 @@ static void print_verifier_state(struct bpf_verifier_env *env,
if (t == PTR_TO_BTF_ID ||
t == PTR_TO_BTF_ID_OR_NULL ||
t == PTR_TO_PERCPU_BTF_ID)
- verbose(env, "%s", kernel_type_name(reg->btf_id));
+ verbose(env, "%s", kernel_type_name(reg->btf, reg->btf_id));
verbose(env, "(id=%d", reg->id);
if (reg_type_may_be_refcounted_or_null(t))
verbose(env, ",ref_obj_id=%d", reg->ref_obj_id);
@@ -1383,7 +1384,8 @@ static void mark_reg_not_init(struct bpf_verifier_env *env,
static void mark_btf_ld_reg(struct bpf_verifier_env *env,
struct bpf_reg_state *regs, u32 regno,
- enum bpf_reg_type reg_type, u32 btf_id)
+ enum bpf_reg_type reg_type,
+ struct btf *btf, u32 btf_id)
{
if (reg_type == SCALAR_VALUE) {
mark_reg_unknown(env, regs, regno);
@@ -1391,6 +1393,7 @@ static void mark_btf_ld_reg(struct bpf_verifier_env *env,
}
mark_reg_known_zero(env, regs, regno);
regs[regno].type = PTR_TO_BTF_ID;
+ regs[regno].btf = btf;
regs[regno].btf_id = btf_id;
}
@@ -2764,7 +2767,7 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
/* check access to 'struct bpf_context' fields. Supports fixed offsets only */
static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
enum bpf_access_type t, enum bpf_reg_type *reg_type,
- u32 *btf_id)
+ struct btf **btf, u32 *btf_id)
{
struct bpf_insn_access_aux info = {
.reg_type = *reg_type,
@@ -2782,10 +2785,12 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off,
*/
*reg_type = info.reg_type;
- if (*reg_type == PTR_TO_BTF_ID || *reg_type == PTR_TO_BTF_ID_OR_NULL)
+ if (*reg_type == PTR_TO_BTF_ID || *reg_type == PTR_TO_BTF_ID_OR_NULL) {
+ *btf = info.btf;
*btf_id = info.btf_id;
- else
+ } else {
env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
+ }
/* remember the offset of last byte accessed in ctx */
if (env->prog->aux->max_ctx_offset < off + size)
env->prog->aux->max_ctx_offset = off + size;
@@ -3297,8 +3302,8 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
int value_regno)
{
struct bpf_reg_state *reg = regs + regno;
- const struct btf_type *t = btf_type_by_id(btf_vmlinux, reg->btf_id);
- const char *tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+ const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
+ const char *tname = btf_name_by_offset(reg->btf, t->name_off);
u32 btf_id;
int ret;
@@ -3319,23 +3324,23 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
}
if (env->ops->btf_struct_access) {
- ret = env->ops->btf_struct_access(&env->log, t, off, size,
- atype, &btf_id);
+ ret = env->ops->btf_struct_access(&env->log, reg->btf, t,
+ off, size, atype, &btf_id);
} else {
if (atype != BPF_READ) {
verbose(env, "only read is supported\n");
return -EACCES;
}
- ret = btf_struct_access(&env->log, t, off, size, atype,
- &btf_id);
+ ret = btf_struct_access(&env->log, reg->btf, t, off, size,
+ atype, &btf_id);
}
if (ret < 0)
return ret;
if (atype == BPF_READ && value_regno >= 0)
- mark_btf_ld_reg(env, regs, value_regno, ret, btf_id);
+ mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id);
return 0;
}
@@ -3385,12 +3390,12 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env,
return -EACCES;
}
- ret = btf_struct_access(&env->log, t, off, size, atype, &btf_id);
+ ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id);
if (ret < 0)
return ret;
if (value_regno >= 0)
- mark_btf_ld_reg(env, regs, value_regno, ret, btf_id);
+ mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id);
return 0;
}
@@ -3466,6 +3471,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
mark_reg_unknown(env, regs, value_regno);
} else if (reg->type == PTR_TO_CTX) {
enum bpf_reg_type reg_type = SCALAR_VALUE;
+ struct btf *btf = NULL;
u32 btf_id = 0;
if (t == BPF_WRITE && value_regno >= 0 &&
@@ -3478,7 +3484,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
if (err < 0)
return err;
- err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf_id);
+ err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, &btf_id);
if (err)
verbose_linfo(env, insn_idx, "; ");
if (!err && t == BPF_READ && value_regno >= 0) {
@@ -3500,8 +3506,10 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
*/
regs[value_regno].subreg_def = DEF_NOT_SUBREG;
if (reg_type == PTR_TO_BTF_ID ||
- reg_type == PTR_TO_BTF_ID_OR_NULL)
+ reg_type == PTR_TO_BTF_ID_OR_NULL) {
+ regs[value_regno].btf = btf;
regs[value_regno].btf_id = btf_id;
+ }
}
regs[value_regno].type = reg_type;
}
@@ -4118,11 +4126,11 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
arg_btf_id = compatible->btf_id;
}
- if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id,
- *arg_btf_id)) {
+ if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+ btf_vmlinux, *arg_btf_id)) {
verbose(env, "R%d is of type %s but %s is expected\n",
- regno, kernel_type_name(reg->btf_id),
- kernel_type_name(*arg_btf_id));
+ regno, kernel_type_name(reg->btf, reg->btf_id),
+ kernel_type_name(btf_vmlinux, *arg_btf_id));
return -EACCES;
}
@@ -4244,6 +4252,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
verbose(env, "Helper has invalid btf_id in R%d\n", regno);
return -EACCES;
}
+ meta->ret_btf = reg->btf;
meta->ret_btf_id = reg->btf_id;
} else if (arg_type == ARG_PTR_TO_SPIN_LOCK) {
if (meta->func_id == BPF_FUNC_spin_lock) {
@@ -5190,16 +5199,16 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
const struct btf_type *t;
mark_reg_known_zero(env, regs, BPF_REG_0);
- t = btf_type_skip_modifiers(btf_vmlinux, meta.ret_btf_id, NULL);
+ t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL);
if (!btf_type_is_struct(t)) {
u32 tsize;
const struct btf_type *ret;
const char *tname;
/* resolve the type size of ksym. */
- ret = btf_resolve_size(btf_vmlinux, t, &tsize);
+ ret = btf_resolve_size(meta.ret_btf, t, &tsize);
if (IS_ERR(ret)) {
- tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+ tname = btf_name_by_offset(meta.ret_btf, t->name_off);
verbose(env, "unable to resolve the size of type '%s': %ld\n",
tname, PTR_ERR(ret));
return -EINVAL;
@@ -5212,6 +5221,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
regs[BPF_REG_0].type =
fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ?
PTR_TO_BTF_ID : PTR_TO_BTF_ID_OR_NULL;
+ regs[BPF_REG_0].btf = meta.ret_btf;
regs[BPF_REG_0].btf_id = meta.ret_btf_id;
}
} else if (fn->ret_type == RET_PTR_TO_BTF_ID_OR_NULL ||
@@ -5228,6 +5238,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
fn->ret_type, func_id_name(func_id), func_id);
return -EINVAL;
}
+ /* current BPF helper definitions are only coming from
+ * built-in code with type IDs from vmlinux BTF
+ */
+ regs[BPF_REG_0].btf = btf_vmlinux;
regs[BPF_REG_0].btf_id = ret_btf_id;
} else {
verbose(env, "unknown return type %d of func %s#%d\n",
@@ -5627,7 +5641,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
if (reg_is_pkt_pointer(ptr_reg)) {
dst_reg->id = ++env->id_gen;
/* something was added to pkt_ptr, set range to zero */
- dst_reg->raw = 0;
+ memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
}
break;
case BPF_SUB:
@@ -5692,7 +5706,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
dst_reg->id = ++env->id_gen;
/* something was added to pkt_ptr, set range to zero */
if (smin_val < 0)
- dst_reg->raw = 0;
+ memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
}
break;
case BPF_AND:
@@ -7744,6 +7758,7 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
break;
case PTR_TO_BTF_ID:
case PTR_TO_PERCPU_BTF_ID:
+ dst_reg->btf = aux->btf_var.btf;
dst_reg->btf_id = aux->btf_var.btf_id;
break;
default:
@@ -9739,6 +9754,7 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
t = btf_type_skip_modifiers(btf_vmlinux, type, NULL);
if (percpu) {
aux->btf_var.reg_type = PTR_TO_PERCPU_BTF_ID;
+ aux->btf_var.btf = btf_vmlinux;
aux->btf_var.btf_id = type;
} else if (!btf_type_is_struct(t)) {
const struct btf_type *ret;
@@ -9757,6 +9773,7 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
aux->btf_var.mem_size = tsize;
} else {
aux->btf_var.reg_type = PTR_TO_BTF_ID;
+ aux->btf_var.btf = btf_vmlinux;
aux->btf_var.btf_id = type;
}
return 0;
@@ -11609,7 +11626,7 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
bpf_log(log, "Tracing programs must provide btf_id\n");
return -EINVAL;
}
- btf = tgt_prog ? tgt_prog->aux->btf : btf_vmlinux;
+ btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
if (!btf) {
bpf_log(log,
"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
@@ -11885,7 +11902,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
return ret;
}
- key = bpf_trampoline_compute_key(tgt_prog, btf_id);
+ key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
tr = bpf_trampoline_get(key, &tgt_info);
if (!tr)
return -ENOMEM;
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 618954f82764..d520e61649c8 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -95,6 +95,7 @@ static bool bpf_tcp_ca_is_valid_access(int off, int size,
}
static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log,
+ const struct btf *btf,
const struct btf_type *t, int off,
int size, enum bpf_access_type atype,
u32 *next_btf_id)
@@ -102,7 +103,7 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log,
size_t end;
if (atype == BPF_READ)
- return btf_struct_access(log, t, off, size, atype, next_btf_id);
+ return btf_struct_access(log, btf, t, off, size, atype, next_btf_id);
if (t != tcp_sock_type) {
bpf_log(log, "only read is supported\n");
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 10/14] bpf: allow to specify kernel module BTFs when attaching BPF programs
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (8 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 09/14] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-04 1:53 ` Alexei Starovoitov
2020-12-03 20:46 ` [PATCH v6 bpf-next 11/14] libbpf: factor out low-level BPF program loading helper Andrii Nakryiko
` (3 subsequent siblings)
13 siblings, 1 reply; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Add ability for user-space programs to specify non-vmlinux BTF when attaching
BTF-powered BPF programs: raw_tp, fentry/fexit/fmod_ret, LSM, etc. For this,
attach_prog_fd (now with the alias name attach_btf_obj_fd) should specify FD
of a module or vmlinux BTF object. For backwards compatibility reasons,
0 denotes vmlinux BTF. Only kernel BTF (vmlinux or module) can be specified.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
include/linux/btf.h | 1 +
include/uapi/linux/bpf.h | 7 ++-
kernel/bpf/btf.c | 5 +++
kernel/bpf/syscall.c | 82 +++++++++++++++++++++-------------
tools/include/uapi/linux/bpf.h | 7 ++-
5 files changed, 69 insertions(+), 33 deletions(-)
diff --git a/include/linux/btf.h b/include/linux/btf.h
index fb608e4de076..4c200f5d242b 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -90,6 +90,7 @@ int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
int btf_get_fd_by_id(u32 id);
u32 btf_obj_id(const struct btf *btf);
+bool btf_is_kernel(const struct btf *btf);
bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
const struct btf_member *m,
u32 expected_offset, u32 expected_size);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c3458ec1f30a..1233f14f659f 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -557,7 +557,12 @@ union bpf_attr {
__aligned_u64 line_info; /* line info */
__u32 line_info_cnt; /* number of bpf_line_info records */
__u32 attach_btf_id; /* in-kernel BTF type id to attach to */
- __u32 attach_prog_fd; /* 0 to attach to vmlinux */
+ union {
+ /* valid prog_fd to attach to bpf prog */
+ __u32 attach_prog_fd;
+ /* or valid module BTF object fd or 0 to attach to vmlinux */
+ __u32 attach_btf_obj_fd;
+ };
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 7a19bf5bfe97..8d6bdb4f4d61 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5738,6 +5738,11 @@ u32 btf_obj_id(const struct btf *btf)
return btf->id;
}
+bool btf_is_kernel(const struct btf *btf)
+{
+ return btf->kernel_btf;
+}
+
static int btf_id_cmp_func(const void *a, const void *b)
{
const int *pa = a, *pb = b;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 184204169949..0cd3cc2af9c1 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1926,12 +1926,16 @@ static void bpf_prog_load_fixup_attach_type(union bpf_attr *attr)
static int
bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
enum bpf_attach_type expected_attach_type,
- u32 btf_id, u32 prog_fd)
+ struct btf *attach_btf, u32 btf_id,
+ struct bpf_prog *dst_prog)
{
if (btf_id) {
if (btf_id > BTF_MAX_TYPE)
return -EINVAL;
+ if (!attach_btf && !dst_prog)
+ return -EINVAL;
+
switch (prog_type) {
case BPF_PROG_TYPE_TRACING:
case BPF_PROG_TYPE_LSM:
@@ -1943,7 +1947,10 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
}
}
- if (prog_fd && prog_type != BPF_PROG_TYPE_TRACING &&
+ if (attach_btf && (!btf_id || dst_prog))
+ return -EINVAL;
+
+ if (dst_prog && prog_type != BPF_PROG_TYPE_TRACING &&
prog_type != BPF_PROG_TYPE_EXT)
return -EINVAL;
@@ -2060,7 +2067,8 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type)
static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
{
enum bpf_prog_type type = attr->prog_type;
- struct bpf_prog *prog;
+ struct bpf_prog *prog, *dst_prog = NULL;
+ struct btf *attach_btf = NULL;
int err;
char license[128];
bool is_gpl;
@@ -2102,44 +2110,56 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
if (is_perfmon_prog_type(type) && !perfmon_capable())
return -EPERM;
+ /* attach_prog_fd/attach_btf_obj_fd can specify fd of either bpf_prog
+ * or btf, we need to check which one it is
+ */
+ if (attr->attach_prog_fd) {
+ dst_prog = bpf_prog_get(attr->attach_prog_fd);
+ if (IS_ERR(dst_prog)) {
+ dst_prog = NULL;
+ attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd);
+ if (IS_ERR(attach_btf))
+ return -EINVAL;
+ if (!btf_is_kernel(attach_btf)) {
+ btf_put(attach_btf);
+ return -EINVAL;
+ }
+ }
+ } else if (attr->attach_btf_id) {
+ /* fall back to vmlinux BTF, if BTF type ID is specified */
+ attach_btf = bpf_get_btf_vmlinux();
+ if (IS_ERR(attach_btf))
+ return PTR_ERR(attach_btf);
+ if (!attach_btf)
+ return -EINVAL;
+ btf_get(attach_btf);
+ }
+
bpf_prog_load_fixup_attach_type(attr);
if (bpf_prog_load_check_attach(type, attr->expected_attach_type,
- attr->attach_btf_id,
- attr->attach_prog_fd))
+ attach_btf, attr->attach_btf_id,
+ dst_prog)) {
+ if (dst_prog)
+ bpf_prog_put(dst_prog);
+ if (attach_btf)
+ btf_put(attach_btf);
return -EINVAL;
+ }
/* plain bpf_prog allocation */
prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
- if (!prog)
+ if (!prog) {
+ if (dst_prog)
+ bpf_prog_put(dst_prog);
+ if (attach_btf)
+ btf_put(attach_btf);
return -ENOMEM;
+ }
prog->expected_attach_type = attr->expected_attach_type;
+ prog->aux->attach_btf = attach_btf;
prog->aux->attach_btf_id = attr->attach_btf_id;
-
- if (attr->attach_btf_id && !attr->attach_prog_fd) {
- struct btf *btf;
-
- btf = bpf_get_btf_vmlinux();
- if (IS_ERR(btf))
- return PTR_ERR(btf);
- if (!btf)
- return -EINVAL;
-
- btf_get(btf);
- prog->aux->attach_btf = btf;
- }
-
- if (attr->attach_prog_fd) {
- struct bpf_prog *dst_prog;
-
- dst_prog = bpf_prog_get(attr->attach_prog_fd);
- if (IS_ERR(dst_prog)) {
- err = PTR_ERR(dst_prog);
- goto free_prog;
- }
- prog->aux->dst_prog = dst_prog;
- }
-
+ prog->aux->dst_prog = dst_prog;
prog->aux->offload_requested = !!attr->prog_ifindex;
prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c3458ec1f30a..1233f14f659f 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -557,7 +557,12 @@ union bpf_attr {
__aligned_u64 line_info; /* line info */
__u32 line_info_cnt; /* number of bpf_line_info records */
__u32 attach_btf_id; /* in-kernel BTF type id to attach to */
- __u32 attach_prog_fd; /* 0 to attach to vmlinux */
+ union {
+ /* valid prog_fd to attach to bpf prog */
+ __u32 attach_prog_fd;
+ /* or valid module BTF object fd or 0 to attach to vmlinux */
+ __u32 attach_btf_obj_fd;
+ };
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* Re: [PATCH v6 bpf-next 10/14] bpf: allow to specify kernel module BTFs when attaching BPF programs
2020-12-03 20:46 ` [PATCH v6 bpf-next 10/14] bpf: allow to specify kernel module BTFs when attaching BPF programs Andrii Nakryiko
@ 2020-12-04 1:53 ` Alexei Starovoitov
2020-12-04 19:31 ` Andrii Nakryiko
0 siblings, 1 reply; 17+ messages in thread
From: Alexei Starovoitov @ 2020-12-04 1:53 UTC (permalink / raw)
To: Andrii Nakryiko; +Cc: bpf, netdev, ast, daniel, kernel-team
On Thu, Dec 03, 2020 at 12:46:30PM -0800, Andrii Nakryiko wrote:
> + if (attr->attach_prog_fd) {
> + dst_prog = bpf_prog_get(attr->attach_prog_fd);
> + if (IS_ERR(dst_prog)) {
> + dst_prog = NULL;
> + attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd);
> + if (IS_ERR(attach_btf))
> + return -EINVAL;
> + if (!btf_is_kernel(attach_btf)) {
> + btf_put(attach_btf);
> + return -EINVAL;
Applied, but please consider follow up with different err code here.
I think we might support this case in the future.
Specifying prog's BTF as a base and attach_btf_id within it might make
user space simpler in some cases. prog's btf covers the whole elf file.
Where prog_fd is a specific prog. That narrow scope isn't really necessary.
So may be return ENOTSUPP here for now? With a hint that this might
work in the future?
^ permalink raw reply [flat|nested] 17+ messages in thread* Re: [PATCH v6 bpf-next 10/14] bpf: allow to specify kernel module BTFs when attaching BPF programs
2020-12-04 1:53 ` Alexei Starovoitov
@ 2020-12-04 19:31 ` Andrii Nakryiko
0 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-04 19:31 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Kernel Team
On Thu, Dec 3, 2020 at 5:54 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Thu, Dec 03, 2020 at 12:46:30PM -0800, Andrii Nakryiko wrote:
> > + if (attr->attach_prog_fd) {
> > + dst_prog = bpf_prog_get(attr->attach_prog_fd);
> > + if (IS_ERR(dst_prog)) {
> > + dst_prog = NULL;
> > + attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd);
> > + if (IS_ERR(attach_btf))
> > + return -EINVAL;
> > + if (!btf_is_kernel(attach_btf)) {
> > + btf_put(attach_btf);
> > + return -EINVAL;
>
> Applied, but please consider follow up with different err code here.
> I think we might support this case in the future.
> Specifying prog's BTF as a base and attach_btf_id within it might make
> user space simpler in some cases. prog's btf covers the whole elf file.
The problem is that there is no link from BTF to bpf_prog. And
multiple instances of bpf_progs can re-use the same BTF object and the
same BTF type ID. That would need to be resolved somehow.
But keeping our options open is a good idea either way. So I'll send a
patch to switch this to -EOPNOTSUPP (I think that's the one we need to
use for user-space).
> Where prog_fd is a specific prog. That narrow scope isn't really necessary.
> So may be return ENOTSUPP here for now? With a hint that this might
> work in the future?
^ permalink raw reply [flat|nested] 17+ messages in thread
* [PATCH v6 bpf-next 11/14] libbpf: factor out low-level BPF program loading helper
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (9 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 10/14] bpf: allow to specify kernel module BTFs when attaching BPF programs Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 12/14] libbpf: support attachment of BPF tracing programs to kernel modules Andrii Nakryiko
` (2 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Refactor low-level API for BPF program loading to not rely on public API
types. This allows painless extension without constant efforts to cleverly not
break backwards compatibility.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/bpf.c | 100 ++++++++++++++++++++++----------
tools/lib/bpf/libbpf.c | 34 +++++------
tools/lib/bpf/libbpf_internal.h | 29 +++++++++
3 files changed, 113 insertions(+), 50 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 4025266d0fb0..5d681ce32b37 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -215,59 +215,52 @@ alloc_zero_tailing_info(const void *orecord, __u32 cnt,
return info;
}
-int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
- char *log_buf, size_t log_buf_sz)
+int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr)
{
void *finfo = NULL, *linfo = NULL;
union bpf_attr attr;
- __u32 log_level;
int fd;
- if (!load_attr || !log_buf != !log_buf_sz)
+ if (!load_attr->log_buf != !load_attr->log_buf_sz)
return -EINVAL;
- log_level = load_attr->log_level;
- if (log_level > (4 | 2 | 1) || (log_level && !log_buf))
+ if (load_attr->log_level > (4 | 2 | 1) || (load_attr->log_level && !load_attr->log_buf))
return -EINVAL;
memset(&attr, 0, sizeof(attr));
attr.prog_type = load_attr->prog_type;
attr.expected_attach_type = load_attr->expected_attach_type;
- if (attr.prog_type == BPF_PROG_TYPE_STRUCT_OPS ||
- attr.prog_type == BPF_PROG_TYPE_LSM) {
- attr.attach_btf_id = load_attr->attach_btf_id;
- } else if (attr.prog_type == BPF_PROG_TYPE_TRACING ||
- attr.prog_type == BPF_PROG_TYPE_EXT) {
- attr.attach_btf_id = load_attr->attach_btf_id;
- attr.attach_prog_fd = load_attr->attach_prog_fd;
- } else {
- attr.prog_ifindex = load_attr->prog_ifindex;
- attr.kern_version = load_attr->kern_version;
- }
- attr.insn_cnt = (__u32)load_attr->insns_cnt;
+
+ attr.attach_btf_id = load_attr->attach_btf_id;
+ attr.attach_prog_fd = load_attr->attach_prog_fd;
+
+ attr.prog_ifindex = load_attr->prog_ifindex;
+ attr.kern_version = load_attr->kern_version;
+
+ attr.insn_cnt = (__u32)load_attr->insn_cnt;
attr.insns = ptr_to_u64(load_attr->insns);
attr.license = ptr_to_u64(load_attr->license);
- attr.log_level = log_level;
- if (log_level) {
- attr.log_buf = ptr_to_u64(log_buf);
- attr.log_size = log_buf_sz;
- } else {
- attr.log_buf = ptr_to_u64(NULL);
- attr.log_size = 0;
+ attr.log_level = load_attr->log_level;
+ if (attr.log_level) {
+ attr.log_buf = ptr_to_u64(load_attr->log_buf);
+ attr.log_size = load_attr->log_buf_sz;
}
attr.prog_btf_fd = load_attr->prog_btf_fd;
+ attr.prog_flags = load_attr->prog_flags;
+
attr.func_info_rec_size = load_attr->func_info_rec_size;
attr.func_info_cnt = load_attr->func_info_cnt;
attr.func_info = ptr_to_u64(load_attr->func_info);
+
attr.line_info_rec_size = load_attr->line_info_rec_size;
attr.line_info_cnt = load_attr->line_info_cnt;
attr.line_info = ptr_to_u64(load_attr->line_info);
+
if (load_attr->name)
memcpy(attr.prog_name, load_attr->name,
- min(strlen(load_attr->name), BPF_OBJ_NAME_LEN - 1));
- attr.prog_flags = load_attr->prog_flags;
+ min(strlen(load_attr->name), (size_t)BPF_OBJ_NAME_LEN - 1));
fd = sys_bpf_prog_load(&attr, sizeof(attr));
if (fd >= 0)
@@ -307,19 +300,19 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
}
fd = sys_bpf_prog_load(&attr, sizeof(attr));
-
if (fd >= 0)
goto done;
}
- if (log_level || !log_buf)
+ if (load_attr->log_level || !load_attr->log_buf)
goto done;
/* Try again with log */
- attr.log_buf = ptr_to_u64(log_buf);
- attr.log_size = log_buf_sz;
+ attr.log_buf = ptr_to_u64(load_attr->log_buf);
+ attr.log_size = load_attr->log_buf_sz;
attr.log_level = 1;
- log_buf[0] = 0;
+ load_attr->log_buf[0] = 0;
+
fd = sys_bpf_prog_load(&attr, sizeof(attr));
done:
free(finfo);
@@ -327,6 +320,49 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
return fd;
}
+int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
+ char *log_buf, size_t log_buf_sz)
+{
+ struct bpf_prog_load_params p = {};
+
+ if (!load_attr || !log_buf != !log_buf_sz)
+ return -EINVAL;
+
+ p.prog_type = load_attr->prog_type;
+ p.expected_attach_type = load_attr->expected_attach_type;
+ switch (p.prog_type) {
+ case BPF_PROG_TYPE_STRUCT_OPS:
+ case BPF_PROG_TYPE_LSM:
+ p.attach_btf_id = load_attr->attach_btf_id;
+ break;
+ case BPF_PROG_TYPE_TRACING:
+ case BPF_PROG_TYPE_EXT:
+ p.attach_btf_id = load_attr->attach_btf_id;
+ p.attach_prog_fd = load_attr->attach_prog_fd;
+ break;
+ default:
+ p.prog_ifindex = load_attr->prog_ifindex;
+ p.kern_version = load_attr->kern_version;
+ }
+ p.insn_cnt = load_attr->insns_cnt;
+ p.insns = load_attr->insns;
+ p.license = load_attr->license;
+ p.log_level = load_attr->log_level;
+ p.log_buf = log_buf;
+ p.log_buf_sz = log_buf_sz;
+ p.prog_btf_fd = load_attr->prog_btf_fd;
+ p.func_info_rec_size = load_attr->func_info_rec_size;
+ p.func_info_cnt = load_attr->func_info_cnt;
+ p.func_info = load_attr->func_info;
+ p.line_info_rec_size = load_attr->line_info_rec_size;
+ p.line_info_cnt = load_attr->line_info_cnt;
+ p.line_info = load_attr->line_info;
+ p.name = load_attr->name;
+ p.prog_flags = load_attr->prog_flags;
+
+ return libbpf__bpf_prog_load(&p);
+}
+
int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
size_t insns_cnt, const char *license,
__u32 kern_version, char *log_buf,
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ca20e493726d..103d66e27406 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6809,7 +6809,7 @@ static int
load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
char *license, __u32 kern_version, int *pfd)
{
- struct bpf_load_program_attr load_attr;
+ struct bpf_prog_load_params load_attr = {};
char *cp, errmsg[STRERR_BUFSIZE];
size_t log_buf_size = 0;
char *log_buf = NULL;
@@ -6828,7 +6828,6 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
if (!insns || !insns_cnt)
return -EINVAL;
- memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
load_attr.prog_type = prog->type;
/* old kernels might not support specifying expected_attach_type */
if (!kernel_supports(FEAT_EXP_ATTACH_TYPE) && prog->sec_def &&
@@ -6839,19 +6838,14 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
if (kernel_supports(FEAT_PROG_NAME))
load_attr.name = prog->name;
load_attr.insns = insns;
- load_attr.insns_cnt = insns_cnt;
+ load_attr.insn_cnt = insns_cnt;
load_attr.license = license;
- if (prog->type == BPF_PROG_TYPE_STRUCT_OPS ||
- prog->type == BPF_PROG_TYPE_LSM) {
- load_attr.attach_btf_id = prog->attach_btf_id;
- } else if (prog->type == BPF_PROG_TYPE_TRACING ||
- prog->type == BPF_PROG_TYPE_EXT) {
- load_attr.attach_prog_fd = prog->attach_prog_fd;
- load_attr.attach_btf_id = prog->attach_btf_id;
- } else {
- load_attr.kern_version = kern_version;
- load_attr.prog_ifindex = prog->prog_ifindex;
- }
+ load_attr.attach_btf_id = prog->attach_btf_id;
+ load_attr.attach_prog_fd = prog->attach_prog_fd;
+ load_attr.attach_btf_id = prog->attach_btf_id;
+ load_attr.kern_version = kern_version;
+ load_attr.prog_ifindex = prog->prog_ifindex;
+
/* specify func_info/line_info only if kernel supports them */
btf_fd = bpf_object__btf_fd(prog->obj);
if (btf_fd >= 0 && kernel_supports(FEAT_BTF_FUNC)) {
@@ -6875,7 +6869,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
*log_buf = 0;
}
- ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
+ load_attr.log_buf = log_buf;
+ load_attr.log_buf_sz = log_buf_size;
+ ret = libbpf__bpf_prog_load(&load_attr);
if (ret >= 0) {
if (log_buf && load_attr.log_level)
@@ -6916,9 +6912,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
pr_warn("-- BEGIN DUMP LOG ---\n");
pr_warn("\n%s\n", log_buf);
pr_warn("-- END LOG --\n");
- } else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
+ } else if (load_attr.insn_cnt >= BPF_MAXINSNS) {
pr_warn("Program too large (%zu insns), at most %d insns\n",
- load_attr.insns_cnt, BPF_MAXINSNS);
+ load_attr.insn_cnt, BPF_MAXINSNS);
ret = -LIBBPF_ERRNO__PROG2BIG;
} else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
/* Wrong program type? */
@@ -6926,7 +6922,9 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
load_attr.expected_attach_type = 0;
- fd = bpf_load_program_xattr(&load_attr, NULL, 0);
+ load_attr.log_buf = NULL;
+ load_attr.log_buf_sz = 0;
+ fd = libbpf__bpf_prog_load(&load_attr);
if (fd >= 0) {
close(fd);
ret = -LIBBPF_ERRNO__PROGTYPE;
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index e569ae63808e..681073a67ae3 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -151,6 +151,35 @@ int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
const char *str_sec, size_t str_len);
+struct bpf_prog_load_params {
+ enum bpf_prog_type prog_type;
+ enum bpf_attach_type expected_attach_type;
+ const char *name;
+ const struct bpf_insn *insns;
+ size_t insn_cnt;
+ const char *license;
+ __u32 kern_version;
+ __u32 attach_prog_fd;
+ __u32 attach_btf_id;
+ __u32 prog_ifindex;
+ __u32 prog_btf_fd;
+ __u32 prog_flags;
+
+ __u32 func_info_rec_size;
+ const void *func_info;
+ __u32 func_info_cnt;
+
+ __u32 line_info_rec_size;
+ const void *line_info;
+ __u32 line_info_cnt;
+
+ __u32 log_level;
+ char *log_buf;
+ size_t log_buf_sz;
+};
+
+int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr);
+
int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size);
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 12/14] libbpf: support attachment of BPF tracing programs to kernel modules
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (10 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 11/14] libbpf: factor out low-level BPF program loading helper Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 13/14] selftests/bpf: add tp_btf CO-RE reloc test for modules Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 14/14] selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module Andrii Nakryiko
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Teach libbpf to search for BTF types in kernel modules for tracing BPF
programs. This allows attachment of raw_tp/fentry/fexit/fmod_ret/etc BPF
program types to tracepoints and functions in kernel modules.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/bpf.c | 5 +-
tools/lib/bpf/libbpf.c | 138 +++++++++++++++++++++++++-------
tools/lib/bpf/libbpf_internal.h | 1 +
3 files changed, 112 insertions(+), 32 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 5d681ce32b37..bba48ff4c5c0 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -231,8 +231,11 @@ int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr)
attr.prog_type = load_attr->prog_type;
attr.expected_attach_type = load_attr->expected_attach_type;
+ if (load_attr->attach_prog_fd)
+ attr.attach_prog_fd = load_attr->attach_prog_fd;
+ else
+ attr.attach_btf_obj_fd = load_attr->attach_btf_obj_fd;
attr.attach_btf_id = load_attr->attach_btf_id;
- attr.attach_prog_fd = load_attr->attach_prog_fd;
attr.prog_ifindex = load_attr->prog_ifindex;
attr.kern_version = load_attr->kern_version;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 103d66e27406..912e01b946fe 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -278,6 +278,7 @@ struct bpf_program {
enum bpf_prog_type type;
enum bpf_attach_type expected_attach_type;
int prog_ifindex;
+ __u32 attach_btf_obj_fd;
__u32 attach_btf_id;
__u32 attach_prog_fd;
void *func_info;
@@ -408,6 +409,7 @@ struct module_btf {
struct btf *btf;
char *name;
__u32 id;
+ int fd;
};
struct bpf_object {
@@ -4766,8 +4768,7 @@ static int load_module_btfs(struct bpf_object *obj)
if (err) {
err = -errno;
pr_warn("failed to get BTF object #%d info: %d\n", id, err);
- close(fd);
- return err;
+ goto err_out;
}
/* ignore non-module BTFs */
@@ -4777,25 +4778,33 @@ static int load_module_btfs(struct bpf_object *obj)
}
btf = btf_get_from_fd(fd, obj->btf_vmlinux);
- close(fd);
if (IS_ERR(btf)) {
pr_warn("failed to load module [%s]'s BTF object #%d: %ld\n",
name, id, PTR_ERR(btf));
- return PTR_ERR(btf);
+ err = PTR_ERR(btf);
+ goto err_out;
}
err = btf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap,
sizeof(*obj->btf_modules), obj->btf_module_cnt + 1);
if (err)
- return err;
+ goto err_out;
mod_btf = &obj->btf_modules[obj->btf_module_cnt++];
mod_btf->btf = btf;
mod_btf->id = id;
+ mod_btf->fd = fd;
mod_btf->name = strdup(name);
- if (!mod_btf->name)
- return -ENOMEM;
+ if (!mod_btf->name) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+ continue;
+
+err_out:
+ close(fd);
+ return err;
}
return 0;
@@ -6841,7 +6850,10 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.insn_cnt = insns_cnt;
load_attr.license = license;
load_attr.attach_btf_id = prog->attach_btf_id;
- load_attr.attach_prog_fd = prog->attach_prog_fd;
+ if (prog->attach_prog_fd)
+ load_attr.attach_prog_fd = prog->attach_prog_fd;
+ else
+ load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd;
load_attr.attach_btf_id = prog->attach_btf_id;
load_attr.kern_version = kern_version;
load_attr.prog_ifindex = prog->prog_ifindex;
@@ -6937,11 +6949,11 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
return ret;
}
-static int libbpf_find_attach_btf_id(struct bpf_program *prog);
+static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id);
int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
{
- int err = 0, fd, i, btf_id;
+ int err = 0, fd, i;
if (prog->obj->loaded) {
pr_warn("prog '%s': can't load after object was loaded\n", prog->name);
@@ -6951,10 +6963,14 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver)
if ((prog->type == BPF_PROG_TYPE_TRACING ||
prog->type == BPF_PROG_TYPE_LSM ||
prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) {
- btf_id = libbpf_find_attach_btf_id(prog);
- if (btf_id <= 0)
- return btf_id;
- prog->attach_btf_id = btf_id;
+ int btf_obj_fd = 0, btf_type_id = 0;
+
+ err = libbpf_find_attach_btf_id(prog, &btf_obj_fd, &btf_type_id);
+ if (err)
+ return err;
+
+ prog->attach_btf_obj_fd = btf_obj_fd;
+ prog->attach_btf_id = btf_type_id;
}
if (prog->instances.nr < 0 || !prog->instances.fds) {
@@ -7467,6 +7483,7 @@ int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
/* clean up module BTFs */
for (i = 0; i < obj->btf_module_cnt; i++) {
+ close(obj->btf_modules[i].fd);
btf__free(obj->btf_modules[i].btf);
free(obj->btf_modules[i].name);
}
@@ -8821,8 +8838,8 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
return btf__find_by_name_kind(btf, btf_type_name, kind);
}
-static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
- enum bpf_attach_type attach_type)
+static inline int find_attach_btf_id(struct btf *btf, const char *name,
+ enum bpf_attach_type attach_type)
{
int err;
@@ -8838,9 +8855,6 @@ static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
else
err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
- if (err <= 0)
- pr_warn("%s is not found in vmlinux BTF\n", name);
-
return err;
}
@@ -8856,7 +8870,10 @@ int libbpf_find_vmlinux_btf_id(const char *name,
return -EINVAL;
}
- err = __find_vmlinux_btf_id(btf, name, attach_type);
+ err = find_attach_btf_id(btf, name, attach_type);
+ if (err <= 0)
+ pr_warn("%s is not found in vmlinux BTF\n", name);
+
btf__free(btf);
return err;
}
@@ -8894,11 +8911,49 @@ static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
return err;
}
-static int libbpf_find_attach_btf_id(struct bpf_program *prog)
+static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name,
+ enum bpf_attach_type attach_type,
+ int *btf_obj_fd, int *btf_type_id)
+{
+ int ret, i;
+
+ ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type);
+ if (ret > 0) {
+ *btf_obj_fd = 0; /* vmlinux BTF */
+ *btf_type_id = ret;
+ return 0;
+ }
+ if (ret != -ENOENT)
+ return ret;
+
+ ret = load_module_btfs(obj);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < obj->btf_module_cnt; i++) {
+ const struct module_btf *mod = &obj->btf_modules[i];
+
+ ret = find_attach_btf_id(mod->btf, attach_name, attach_type);
+ if (ret > 0) {
+ *btf_obj_fd = mod->fd;
+ *btf_type_id = ret;
+ return 0;
+ }
+ if (ret == -ENOENT)
+ continue;
+
+ return ret;
+ }
+
+ return -ESRCH;
+}
+
+static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd, int *btf_type_id)
{
enum bpf_attach_type attach_type = prog->expected_attach_type;
__u32 attach_prog_fd = prog->attach_prog_fd;
- const char *name = prog->sec_name;
+ const char *name = prog->sec_name, *attach_name;
+ const struct bpf_sec_def *sec = NULL;
int i, err;
if (!name)
@@ -8909,17 +8964,37 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog)
continue;
if (strncmp(name, section_defs[i].sec, section_defs[i].len))
continue;
- if (attach_prog_fd)
- err = libbpf_find_prog_btf_id(name + section_defs[i].len,
- attach_prog_fd);
- else
- err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux,
- name + section_defs[i].len,
- attach_type);
+
+ sec = §ion_defs[i];
+ break;
+ }
+
+ if (!sec) {
+ pr_warn("failed to identify BTF ID based on ELF section name '%s'\n", name);
+ return -ESRCH;
+ }
+ attach_name = name + sec->len;
+
+ /* BPF program's BTF ID */
+ if (attach_prog_fd) {
+ err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd);
+ if (err < 0) {
+ pr_warn("failed to find BPF program (FD %d) BTF ID for '%s': %d\n",
+ attach_prog_fd, attach_name, err);
+ return err;
+ }
+ *btf_obj_fd = 0;
+ *btf_type_id = err;
+ return 0;
+ }
+
+ /* kernel/module BTF ID */
+ err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id);
+ if (err) {
+ pr_warn("failed to find kernel BTF type ID of '%s': %d\n", attach_name, err);
return err;
}
- pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
- return -ESRCH;
+ return 0;
}
int libbpf_attach_type_by_name(const char *name,
@@ -10808,6 +10883,7 @@ int bpf_program__set_attach_target(struct bpf_program *prog,
return btf_id;
prog->attach_btf_id = btf_id;
+ prog->attach_btf_obj_fd = 0;
prog->attach_prog_fd = attach_prog_fd;
return 0;
}
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 681073a67ae3..969d0ac592ba 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -160,6 +160,7 @@ struct bpf_prog_load_params {
const char *license;
__u32 kern_version;
__u32 attach_prog_fd;
+ __u32 attach_btf_obj_fd;
__u32 attach_btf_id;
__u32 prog_ifindex;
__u32 prog_btf_fd;
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 13/14] selftests/bpf: add tp_btf CO-RE reloc test for modules
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (11 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 12/14] libbpf: support attachment of BPF tracing programs to kernel modules Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
2020-12-03 20:46 ` [PATCH v6 bpf-next 14/14] selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module Andrii Nakryiko
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Add another CO-RE relocation test for kernel module relocations. This time for
tp_btf with direct memory reads.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
.../selftests/bpf/prog_tests/core_reloc.c | 3 +-
.../bpf/progs/test_core_reloc_module.c | 32 ++++++++++++++++++-
2 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
index bb980848cd77..06eb956ff7bb 100644
--- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
@@ -514,7 +514,8 @@ static struct core_reloc_test_case test_cases[] = {
},
/* validate we can find kernel module BTF types for relocs/attach */
- MODULES_CASE("module", "raw_tp/bpf_testmod_test_read", "bpf_testmod_test_read"),
+ MODULES_CASE("module_probed", "raw_tp/bpf_testmod_test_read", "bpf_testmod_test_read"),
+ MODULES_CASE("module_direct", "tp_btf/bpf_testmod_test_read", NULL),
/* validate BPF program can use multiple flavors to match against
* single target BTF type
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_module.c b/tools/testing/selftests/bpf/progs/test_core_reloc_module.c
index d1840c1a9d36..56363959f7b0 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_module.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_module.c
@@ -36,7 +36,7 @@ struct core_reloc_module_output {
};
SEC("raw_tp/bpf_testmod_test_read")
-int BPF_PROG(test_core_module,
+int BPF_PROG(test_core_module_probed,
struct task_struct *task,
struct bpf_testmod_test_read_ctx *read_ctx)
{
@@ -64,3 +64,33 @@ int BPF_PROG(test_core_module,
return 0;
}
+
+SEC("tp_btf/bpf_testmod_test_read")
+int BPF_PROG(test_core_module_direct,
+ struct task_struct *task,
+ struct bpf_testmod_test_read_ctx *read_ctx)
+{
+ struct core_reloc_module_output *out = (void *)&data.out;
+ __u64 pid_tgid = bpf_get_current_pid_tgid();
+ __u32 real_tgid = (__u32)(pid_tgid >> 32);
+ __u32 real_pid = (__u32)pid_tgid;
+
+ if (data.my_pid_tgid != pid_tgid)
+ return 0;
+
+ if (task->pid != real_pid || task->tgid != real_tgid)
+ return 0;
+
+ out->len = read_ctx->len;
+ out->off = read_ctx->off;
+
+ out->read_ctx_sz = bpf_core_type_size(struct bpf_testmod_test_read_ctx);
+ out->read_ctx_exists = bpf_core_type_exists(struct bpf_testmod_test_read_ctx);
+ out->buf_exists = bpf_core_field_exists(read_ctx->buf);
+ out->off_exists = bpf_core_field_exists(read_ctx->off);
+ out->len_exists = bpf_core_field_exists(read_ctx->len);
+
+ out->comm_len = BPF_CORE_READ_STR_INTO(&out->comm, task, comm);
+
+ return 0;
+}
--
2.24.1
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v6 bpf-next 14/14] selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module
2020-12-03 20:46 [PATCH v6 bpf-next 00/14] Support BTF-powered BPF tracing programs for kernel modules Andrii Nakryiko
` (12 preceding siblings ...)
2020-12-03 20:46 ` [PATCH v6 bpf-next 13/14] selftests/bpf: add tp_btf CO-RE reloc test for modules Andrii Nakryiko
@ 2020-12-03 20:46 ` Andrii Nakryiko
13 siblings, 0 replies; 17+ messages in thread
From: Andrii Nakryiko @ 2020-12-03 20:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Add new selftest checking attachment of fentry/fexit/fmod_ret (and raw
tracepoint ones for completeness) BPF programs to kernel module function.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
.../selftests/bpf/prog_tests/module_attach.c | 53 +++++++++++++++
.../selftests/bpf/progs/test_module_attach.c | 66 +++++++++++++++++++
2 files changed, 119 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/module_attach.c
create mode 100644 tools/testing/selftests/bpf/progs/test_module_attach.c
diff --git a/tools/testing/selftests/bpf/prog_tests/module_attach.c b/tools/testing/selftests/bpf/prog_tests/module_attach.c
new file mode 100644
index 000000000000..4b65e9918764
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/module_attach.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include <test_progs.h>
+#include "test_module_attach.skel.h"
+
+static int duration;
+
+static int trigger_module_test_read(int read_sz)
+{
+ int fd, err;
+
+ fd = open("/sys/kernel/bpf_testmod", O_RDONLY);
+ err = -errno;
+ if (CHECK(fd < 0, "testmod_file_open", "failed: %d\n", err))
+ return err;
+
+ read(fd, NULL, read_sz);
+ close(fd);
+
+ return 0;
+}
+
+void test_module_attach(void)
+{
+ const int READ_SZ = 456;
+ struct test_module_attach* skel;
+ struct test_module_attach__bss *bss;
+ int err;
+
+ skel = test_module_attach__open_and_load();
+ if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+ return;
+
+ bss = skel->bss;
+
+ err = test_module_attach__attach(skel);
+ if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+ goto cleanup;
+
+ /* trigger tracepoint */
+ ASSERT_OK(trigger_module_test_read(READ_SZ), "trigger_read");
+
+ ASSERT_EQ(bss->raw_tp_read_sz, READ_SZ, "raw_tp");
+ ASSERT_EQ(bss->tp_btf_read_sz, READ_SZ, "tp_btf");
+ ASSERT_EQ(bss->fentry_read_sz, READ_SZ, "fentry");
+ ASSERT_EQ(bss->fexit_read_sz, READ_SZ, "fexit");
+ ASSERT_EQ(bss->fexit_ret, -EIO, "fexit_tet");
+ ASSERT_EQ(bss->fmod_ret_read_sz, READ_SZ, "fmod_ret");
+
+cleanup:
+ test_module_attach__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c
new file mode 100644
index 000000000000..b563563df172
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_module_attach.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+#include "../bpf_testmod/bpf_testmod.h"
+
+__u32 raw_tp_read_sz = 0;
+
+SEC("raw_tp/bpf_testmod_test_read")
+int BPF_PROG(handle_raw_tp,
+ struct task_struct *task, struct bpf_testmod_test_read_ctx *read_ctx)
+{
+ raw_tp_read_sz = BPF_CORE_READ(read_ctx, len);
+ return 0;
+}
+
+__u32 tp_btf_read_sz = 0;
+
+SEC("tp_btf/bpf_testmod_test_read")
+int BPF_PROG(handle_tp_btf,
+ struct task_struct *task, struct bpf_testmod_test_read_ctx *read_ctx)
+{
+ tp_btf_read_sz = read_ctx->len;
+ return 0;
+}
+
+__u32 fentry_read_sz = 0;
+
+SEC("fentry/bpf_testmod_test_read")
+int BPF_PROG(handle_fentry,
+ struct file *file, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
+{
+ fentry_read_sz = len;
+ return 0;
+}
+
+__u32 fexit_read_sz = 0;
+int fexit_ret = 0;
+
+SEC("fexit/bpf_testmod_test_read")
+int BPF_PROG(handle_fexit,
+ struct file *file, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len,
+ int ret)
+{
+ fexit_read_sz = len;
+ fexit_ret = ret;
+ return 0;
+}
+
+__u32 fmod_ret_read_sz = 0;
+
+SEC("fmod_ret/bpf_testmod_test_read")
+int BPF_PROG(handle_fmod_ret,
+ struct file *file, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
+{
+ fmod_ret_read_sz = len;
+ return 0; /* don't override the exit code */
+}
+
+char _license[] SEC("license") = "GPL";
--
2.24.1
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