* [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments
@ 2020-11-21 2:46 Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier Andrii Nakryiko
` (6 more replies)
0 siblings, 7 replies; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Building on top of two previous patch sets ([0] and not yet landed [1]), this
patch sets extends kernel and libbpf with support for attaching BTF-powered
raw tracepoint (tp_btf) and tracing (fentry/fexit/fmod_ret/lsm) BPF programs
to BPF hooks defined in kernel modules.
Kernel UAPI for BPF_PROG_LOAD is extended with extra parameter
(attach_btf_obj_id) which allows to specify kernel module BTF in which the BTF
type is identifed by attach_btf_id.
From end user perspective there are no extra actions that need to happen.
Libbpf will continue searching across all kernel module BTFs, if desired
attach BTF type is not found in vmlinux. That way it doesn't matter if BPF
hook that user is trying to attach to is built-in into vmlinux image or is
loaded in kernel module.
Currently pahole doesn't generate BTF_KIND_FUNC info for ftrace-able static
functions in kernel modules, so expose traced function in bpf_sidecar.ko. Once
pahole is enhanced, we can go back to static function.
[0] https://patchwork.kernel.org/project/netdevbpf/list/?series=380759&state=*
[1] https://patchwork.kernel.org/project/netdevbpf/list/?series=387965&state=*
Andrii Nakryiko (7):
bpf: remove hard-coded btf_vmlinux assumption from BPF verifier
bpf: allow to specify kernel module BTFs when attaching BPF programs
libbpf: factor out low-level BPF program loading helper
libbpf: support attachment of BPF tracing programs to kernel modules
selftests/bpf: add tp_btf CO-RE reloc test for modules
selftests/bpf: make BPF sidecar traceable function global
selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module
include/linux/bpf.h | 13 +-
include/linux/bpf_verifier.h | 24 ++-
include/linux/btf.h | 7 +-
include/uapi/linux/bpf.h | 1 +
kernel/bpf/btf.c | 90 ++++++++----
kernel/bpf/syscall.c | 44 +++++-
kernel/bpf/verifier.c | 77 ++++++----
net/ipv4/bpf_tcp_ca.c | 3 +-
tools/include/uapi/linux/bpf.h | 1 +
tools/lib/bpf/bpf.c | 101 +++++++++----
tools/lib/bpf/libbpf.c | 139 +++++++++++++-----
tools/lib/bpf/libbpf_internal.h | 30 ++++
.../selftests/bpf/bpf_sidecar/bpf_sidecar.c | 3 +-
.../selftests/bpf/prog_tests/core_reloc.c | 3 +-
.../selftests/bpf/prog_tests/module_attach.c | 53 +++++++
.../bpf/progs/test_core_reloc_module.c | 32 +++-
.../selftests/bpf/progs/test_module_attach.c | 66 +++++++++
17 files changed, 541 insertions(+), 146 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/module_attach.c
create mode 100644 tools/testing/selftests/bpf/progs/test_module_attach.c
--
2.24.1
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
@ 2020-11-21 2:46 ` Andrii Nakryiko
2020-11-29 1:56 ` Alexei Starovoitov
2020-11-21 2:46 ` [PATCH bpf-next 2/7] bpf: allow to specify kernel module BTFs when attaching BPF programs Andrii Nakryiko
` (5 subsequent siblings)
6 siblings, 1 reply; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 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 | 24 ++++++++---
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, 146 insertions(+), 65 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e1bcb6d7345c..2f3b22887ef3 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);
@@ -1430,12 +1434,13 @@ 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..12ded13d2885 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>
@@ -52,12 +53,19 @@ 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;
@@ -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 f3fe9f53f93c..5ee00611af53 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1726,6 +1726,8 @@ static void __bpf_prog_put_rcu(struct rcu_head *rcu)
bpf_prog_uncharge_memlock(aux->prog);
security_bpf_prog_free(aux);
bpf_prog_free(aux->prog);
+ if (aux->attach_btf)
+ btf_put(aux->attach_btf);
}
static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred)
@@ -2155,6 +2157,20 @@ 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;
@@ -2255,6 +2271,8 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
free_prog_sec:
security_bpf_prog_free(prog->aux);
free_prog_nouncharge:
+ if (prog->aux->attach_btf)
+ btf_put(prog->aux->attach_btf);
bpf_prog_free(prog);
return err;
}
@@ -2612,7 +2630,7 @@ 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);
@@ -3589,7 +3607,7 @@ 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;
@@ -3692,7 +3710,7 @@ 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 fb2943ea715d..34dba0fba981 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:
@@ -9728,6 +9743,7 @@ 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;
@@ -9746,6 +9762,7 @@ 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;
@@ -11598,7 +11615,7 @@ 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");
@@ -11874,7 +11891,7 @@ 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] 14+ messages in thread
* [PATCH bpf-next 2/7] bpf: allow to specify kernel module BTFs when attaching BPF programs
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier Andrii Nakryiko
@ 2020-11-21 2:46 ` Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 3/7] libbpf: factor out low-level BPF program loading helper Andrii Nakryiko
` (4 subsequent siblings)
6 siblings, 0 replies; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 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,
add attach_btf_obj_id field which contains BTF object ID for either vmlinux or
module. For backwards compatibility (and simplicity) 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 | 2 ++
include/uapi/linux/bpf.h | 1 +
kernel/bpf/btf.c | 25 +++++++++++++++++++------
kernel/bpf/syscall.c | 22 +++++++++++++++++++---
tools/include/uapi/linux/bpf.h | 1 +
5 files changed, 42 insertions(+), 9 deletions(-)
diff --git a/include/linux/btf.h b/include/linux/btf.h
index fb608e4de076..53ce2bc6dc54 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -89,7 +89,9 @@ 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);
+struct btf *btf_get_by_id(int 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 3ca6146f001a..782169dc41e0 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -558,6 +558,7 @@ union bpf_attr {
__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 */
+ __u32 attach_btf_obj_id; /* vmlinux/module BTF object ID for BTF type */
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 7a19bf5bfe97..12876b272c6b 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5652,6 +5652,19 @@ struct btf *btf_get_by_fd(int fd)
return btf;
}
+struct btf *btf_get_by_id(int id)
+{
+ struct btf *btf;
+
+ rcu_read_lock();
+ btf = idr_find(&btf_idr, id);
+ if (!btf || !refcount_inc_not_zero(&btf->refcnt))
+ btf = ERR_PTR(-ENOENT);
+ rcu_read_unlock();
+
+ return btf;
+}
+
int btf_get_info_by_fd(const struct btf *btf,
const union bpf_attr *attr,
union bpf_attr __user *uattr)
@@ -5717,12 +5730,7 @@ int btf_get_fd_by_id(u32 id)
struct btf *btf;
int fd;
- rcu_read_lock();
- btf = idr_find(&btf_idr, id);
- if (!btf || !refcount_inc_not_zero(&btf->refcnt))
- btf = ERR_PTR(-ENOENT);
- rcu_read_unlock();
-
+ btf = btf_get_by_id(id);
if (IS_ERR(btf))
return PTR_ERR(btf);
@@ -5738,6 +5746,11 @@ 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 5ee00611af53..3af073642664 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1968,7 +1968,7 @@ 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)
+ u32 btf_obj_id, u32 btf_id, u32 prog_fd)
{
if (btf_id) {
if (btf_id > BTF_MAX_TYPE)
@@ -1985,6 +1985,9 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
}
}
+ if (btf_obj_id && (!btf_id || prog_fd))
+ return -EINVAL;
+
if (prog_fd && prog_type != BPF_PROG_TYPE_TRACING &&
prog_type != BPF_PROG_TYPE_EXT)
return -EINVAL;
@@ -2097,7 +2100,7 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type)
}
/* last field in 'union bpf_attr' used by this command */
-#define BPF_PROG_LOAD_LAST_FIELD attach_prog_fd
+#define BPF_PROG_LOAD_LAST_FIELD attach_btf_obj_id
static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
{
@@ -2146,6 +2149,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
bpf_prog_load_fixup_attach_type(attr);
if (bpf_prog_load_check_attach(type, attr->expected_attach_type,
+ attr->attach_btf_obj_id,
attr->attach_btf_id,
attr->attach_prog_fd))
return -EINVAL;
@@ -2158,7 +2162,19 @@ 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) {
+ if (attr->attach_btf_obj_id) {
+ struct btf *btf;
+
+ btf = btf_get_by_id(attr->attach_btf_obj_id);
+ if (IS_ERR(btf))
+ return PTR_ERR(btf);
+ if (!btf_is_kernel(btf)) {
+ btf_put(btf);
+ return -EINVAL;
+ }
+
+ prog->aux->attach_btf = btf;
+ } else if (attr->attach_btf_id && !attr->attach_prog_fd) {
struct btf *btf;
btf = bpf_get_btf_vmlinux();
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 3ca6146f001a..782169dc41e0 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -558,6 +558,7 @@ union bpf_attr {
__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 */
+ __u32 attach_btf_obj_id; /* vmlinux/module BTF object ID for BTF type */
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
--
2.24.1
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH bpf-next 3/7] libbpf: factor out low-level BPF program loading helper
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 2/7] bpf: allow to specify kernel module BTFs when attaching BPF programs Andrii Nakryiko
@ 2020-11-21 2:46 ` Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 4/7] libbpf: support attachment of BPF tracing programs to kernel modules Andrii Nakryiko
` (3 subsequent siblings)
6 siblings, 0 replies; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 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 d27e34133973..e371ef91f5e8 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -214,59 +214,52 @@ 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)
@@ -306,19 +299,19 @@ 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);
@@ -326,6 +319,49 @@ 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 ac1ff4e7741a..3425e594132b 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;
@@ -6818,7 +6818,6 @@ 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 &&
@@ -6829,19 +6828,14 @@ 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)) {
@@ -6865,7 +6859,9 @@ 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)
@@ -6906,9 +6902,9 @@ 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? */
@@ -6916,7 +6912,9 @@ 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] 14+ messages in thread
* [PATCH bpf-next 4/7] libbpf: support attachment of BPF tracing programs to kernel modules
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
` (2 preceding siblings ...)
2020-11-21 2:46 ` [PATCH bpf-next 3/7] libbpf: factor out low-level BPF program loading helper Andrii Nakryiko
@ 2020-11-21 2:46 ` Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules Andrii Nakryiko
` (2 subsequent siblings)
6 siblings, 0 replies; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 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 | 1 +
tools/lib/bpf/libbpf.c | 105 ++++++++++++++++++++++++++------
tools/lib/bpf/libbpf_internal.h | 1 +
3 files changed, 87 insertions(+), 20 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index e371ef91f5e8..dfdad932ef72 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -230,6 +230,7 @@ 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;
+ attr.attach_btf_obj_id = load_attr->attach_btf_obj_id;
attr.attach_btf_id = load_attr->attach_btf_id;
attr.attach_prog_fd = load_attr->attach_prog_fd;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3425e594132b..c3ca34998a76 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_id;
__u32 attach_btf_id;
__u32 attach_prog_fd;
void *func_info;
@@ -6832,6 +6833,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.license = license;
load_attr.attach_btf_id = prog->attach_btf_id;
load_attr.attach_prog_fd = prog->attach_prog_fd;
+ load_attr.attach_btf_obj_id = prog->attach_btf_obj_id;
load_attr.attach_btf_id = prog->attach_btf_id;
load_attr.kern_version = kern_version;
load_attr.prog_ifindex = prog->prog_ifindex;
@@ -6927,11 +6929,11 @@ 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_id, 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);
@@ -6941,10 +6943,14 @@ 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_id = 0, btf_type_id = 0;
+
+ err = libbpf_find_attach_btf_id(prog, &btf_obj_id, &btf_type_id);
+ if (err)
+ return err;
+
+ prog->attach_btf_id = btf_type_id;
+ prog->attach_btf_obj_id = btf_obj_id;
}
if (prog->instances.nr < 0 || !prog->instances.fds) {
@@ -8796,8 +8802,8 @@ 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;
@@ -8828,7 +8834,7 @@ 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);
@@ -8869,11 +8875,49 @@ 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_id, int *btf_type_id)
+{
+ int ret, i;
+
+ ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type);
+ if (ret > 0) {
+ *btf_obj_id = 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_id = mod->id;
+ *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_id, 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)
@@ -8884,17 +8928,37 @@ 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_id = 0;
+ *btf_type_id = err;
+ return 0;
+ }
+
+ /* kernel/module BTF ID */
+ err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_id, 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,
@@ -10783,6 +10847,7 @@ int bpf_program__set_attach_target(struct bpf_program *prog,
return btf_id;
prog->attach_btf_id = btf_id;
+ prog->attach_btf_obj_id = 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..36236b4430ff 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_id;
__u32 attach_btf_id;
__u32 prog_ifindex;
__u32 prog_btf_fd;
--
2.24.1
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
` (3 preceding siblings ...)
2020-11-21 2:46 ` [PATCH bpf-next 4/7] libbpf: support attachment of BPF tracing programs to kernel modules Andrii Nakryiko
@ 2020-11-21 2:46 ` Andrii Nakryiko
2020-11-29 1:59 ` Alexei Starovoitov
2020-11-21 2:46 ` [PATCH bpf-next 6/7] selftests/bpf: make BPF sidecar traceable function global Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 7/7] selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module Andrii Nakryiko
6 siblings, 1 reply; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 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 b3f14e3d9077..85c9cf8e3994 100644
--- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
@@ -512,7 +512,8 @@ 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_sidecar_test_read", "bpf_sidecar_test_read"),
+ MODULES_CASE("module_probed", "raw_tp/bpf_sidecar_test_read", "bpf_sidecar_test_read"),
+ MODULES_CASE("module_direct", "tp_btf/bpf_sidecar_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 4630301de259..f336c0565d47 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_sidecar_test_read")
-int BPF_PROG(test_core_module,
+int BPF_PROG(test_core_module_probed,
struct task_struct *task,
struct bpf_sidecar_test_read_ctx *read_ctx)
{
@@ -64,3 +64,33 @@ int BPF_PROG(test_core_module,
return 0;
}
+
+SEC("tp_btf/bpf_sidecar_test_read")
+int BPF_PROG(test_core_module_direct,
+ struct task_struct *task,
+ struct bpf_sidecar_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_sidecar_test_read_ctx);
+ out->read_ctx_exists = bpf_core_type_exists(struct bpf_sidecar_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] 14+ messages in thread
* [PATCH bpf-next 6/7] selftests/bpf: make BPF sidecar traceable function global
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
` (4 preceding siblings ...)
2020-11-21 2:46 ` [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules Andrii Nakryiko
@ 2020-11-21 2:46 ` Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 7/7] selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module Andrii Nakryiko
6 siblings, 0 replies; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 UTC (permalink / raw)
To: bpf, netdev, ast, daniel; +Cc: andrii, kernel-team
Pahole currently isn't able to generate BTF for static functions in kernel
modules, so make sure traced sidecar function is global.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar.c b/tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar.c
index 46f48c20d99b..a2f6d4a15a3f 100644
--- a/tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar.c
+++ b/tools/testing/selftests/bpf/bpf_sidecar/bpf_sidecar.c
@@ -10,7 +10,7 @@
#define CREATE_TRACE_POINTS
#include "bpf_sidecar-events.h"
-static noinline ssize_t
+noinline ssize_t
bpf_sidecar_test_read(struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t len)
@@ -25,6 +25,7 @@ bpf_sidecar_test_read(struct file *file, struct kobject *kobj,
return -EIO; /* always fail */
}
+EXPORT_SYMBOL(bpf_sidecar_test_read);
ALLOW_ERROR_INJECTION(bpf_sidecar_test_read, ERRNO);
static struct bin_attribute bin_attr_bpf_sidecar_file __ro_after_init = {
--
2.24.1
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH bpf-next 7/7] selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
` (5 preceding siblings ...)
2020-11-21 2:46 ` [PATCH bpf-next 6/7] selftests/bpf: make BPF sidecar traceable function global Andrii Nakryiko
@ 2020-11-21 2:46 ` Andrii Nakryiko
6 siblings, 0 replies; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-21 2:46 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..c871ac073bcf
--- /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_sidecar", O_RDONLY);
+ err = -errno;
+ if (CHECK(fd < 0, "sidecar_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..4c79261d95e6
--- /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_sidecar/bpf_sidecar.h"
+
+__u32 raw_tp_read_sz = 0;
+
+SEC("raw_tp/bpf_sidecar_test_read")
+int BPF_PROG(handle_raw_tp,
+ struct task_struct *task, struct bpf_sidecar_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_sidecar_test_read")
+int BPF_PROG(handle_tp_btf,
+ struct task_struct *task, struct bpf_sidecar_test_read_ctx *read_ctx)
+{
+ tp_btf_read_sz = read_ctx->len;
+ return 0;
+}
+
+__u32 fentry_read_sz = 0;
+
+SEC("fentry/bpf_sidecar_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_sidecar_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_sidecar_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
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier
2020-11-21 2:46 ` [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier Andrii Nakryiko
@ 2020-11-29 1:56 ` Alexei Starovoitov
2020-11-30 23:04 ` Andrii Nakryiko
0 siblings, 1 reply; 14+ messages in thread
From: Alexei Starovoitov @ 2020-11-29 1:56 UTC (permalink / raw)
To: Andrii Nakryiko; +Cc: bpf, netdev, ast, daniel, kernel-team
On Fri, Nov 20, 2020 at 06:46:10PM -0800, Andrii Nakryiko wrote:
>
> @@ -52,12 +53,19 @@ 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;
> + };
bpf_reg_state is the main structure contributing to the verifier memory consumption.
Is it possible to do the tracking without growing it?
>
> 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;
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules
2020-11-21 2:46 ` [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules Andrii Nakryiko
@ 2020-11-29 1:59 ` Alexei Starovoitov
2020-11-30 22:52 ` Andrii Nakryiko
0 siblings, 1 reply; 14+ messages in thread
From: Alexei Starovoitov @ 2020-11-29 1:59 UTC (permalink / raw)
To: Andrii Nakryiko; +Cc: bpf, netdev, ast, daniel, kernel-team
On Fri, Nov 20, 2020 at 06:46:14PM -0800, Andrii Nakryiko wrote:
>
> SEC("raw_tp/bpf_sidecar_test_read")
> -int BPF_PROG(test_core_module,
> +int BPF_PROG(test_core_module_probed,
> struct task_struct *task,
> struct bpf_sidecar_test_read_ctx *read_ctx)
> {
> @@ -64,3 +64,33 @@ int BPF_PROG(test_core_module,
>
> return 0;
> }
> +
> +SEC("tp_btf/bpf_sidecar_test_read")
> +int BPF_PROG(test_core_module_direct,
> + struct task_struct *task,
> + struct bpf_sidecar_test_read_ctx *read_ctx)
"sidecar" is such an overused name.
I didn't like it earlier, but seeing that it here again and again I couldn't help it.
Could you please pick a different name for kernel module?
It's just a kernel module for testing. Just call it so. No need for fancy name.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules
2020-11-29 1:59 ` Alexei Starovoitov
@ 2020-11-30 22:52 ` Andrii Nakryiko
2020-11-30 22:55 ` Alexei Starovoitov
0 siblings, 1 reply; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-30 22:52 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Kernel Team
On Sat, Nov 28, 2020 at 5:59 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Fri, Nov 20, 2020 at 06:46:14PM -0800, Andrii Nakryiko wrote:
> >
> > SEC("raw_tp/bpf_sidecar_test_read")
> > -int BPF_PROG(test_core_module,
> > +int BPF_PROG(test_core_module_probed,
> > struct task_struct *task,
> > struct bpf_sidecar_test_read_ctx *read_ctx)
> > {
> > @@ -64,3 +64,33 @@ int BPF_PROG(test_core_module,
> >
> > return 0;
> > }
> > +
> > +SEC("tp_btf/bpf_sidecar_test_read")
> > +int BPF_PROG(test_core_module_direct,
> > + struct task_struct *task,
> > + struct bpf_sidecar_test_read_ctx *read_ctx)
>
> "sidecar" is such an overused name.
How about "sidekick"? :) Its definition matches quite closely for what
we are doing with it ("person's assistant or close associate,
especially one who has less authority than that person.")?
But if you still hate it, I can call it just "bpf_selftest" or
"bpf_test" or "bpf_testmod", however boring that is... ;)
> I didn't like it earlier, but seeing that it here again and again I couldn't help it.
> Could you please pick a different name for kernel module?
> It's just a kernel module for testing. Just call it so. No need for fancy name.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules
2020-11-30 22:52 ` Andrii Nakryiko
@ 2020-11-30 22:55 ` Alexei Starovoitov
0 siblings, 0 replies; 14+ messages in thread
From: Alexei Starovoitov @ 2020-11-30 22:55 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Kernel Team
On Mon, Nov 30, 2020 at 2:52 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Sat, Nov 28, 2020 at 5:59 PM Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
> >
> > On Fri, Nov 20, 2020 at 06:46:14PM -0800, Andrii Nakryiko wrote:
> > >
> > > SEC("raw_tp/bpf_sidecar_test_read")
> > > -int BPF_PROG(test_core_module,
> > > +int BPF_PROG(test_core_module_probed,
> > > struct task_struct *task,
> > > struct bpf_sidecar_test_read_ctx *read_ctx)
> > > {
> > > @@ -64,3 +64,33 @@ int BPF_PROG(test_core_module,
> > >
> > > return 0;
> > > }
> > > +
> > > +SEC("tp_btf/bpf_sidecar_test_read")
> > > +int BPF_PROG(test_core_module_direct,
> > > + struct task_struct *task,
> > > + struct bpf_sidecar_test_read_ctx *read_ctx)
> >
> > "sidecar" is such an overused name.
>
> How about "sidekick"? :) Its definition matches quite closely for what
> we are doing with it ("person's assistant or close associate,
> especially one who has less authority than that person.")?
>
> But if you still hate it, I can call it just "bpf_selftest" or
> "bpf_test" or "bpf_testmod", however boring that is... ;)
bpf_testmod sounds the best to me :)
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier
2020-11-29 1:56 ` Alexei Starovoitov
@ 2020-11-30 23:04 ` Andrii Nakryiko
2020-12-01 1:18 ` Alexei Starovoitov
0 siblings, 1 reply; 14+ messages in thread
From: Andrii Nakryiko @ 2020-11-30 23:04 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Kernel Team
On Sat, Nov 28, 2020 at 5:56 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Fri, Nov 20, 2020 at 06:46:10PM -0800, Andrii Nakryiko wrote:
> >
> > @@ -52,12 +53,19 @@ 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;
> > + };
>
> bpf_reg_state is the main structure contributing to the verifier memory consumption.
> Is it possible to do the tracking without growing it?
The only way to keep this at 8 bytes in the existing union is to use
ID for BTF, but that has tons of problems: need to do look up all the
time, plus there is now a possibility of that BTF instance going away
(e.g., if kernel module is unloaded), etc. Pain.
But, I just looked at bpf_reg_state with pahole, and there are two
4-byte holes: before this union and after ref_obj_id. So if I move
"off" to before the union, the overall size of the struct won't
change, even if the union itself grows to 16 bytes. And it won't break
states_equal() logic, from what I can see.
So with that, bpf_reg_state BEFORE:
struct bpf_reg_state {
enum bpf_reg_type type; /* 0 4 */
/* XXX 4 bytes hole, try to pack */
union {
int range; /* 8 4 */
struct bpf_map * map_ptr; /* 8 8 */
u32 btf_id; /* 8 4 */
u32 mem_size; /* 8 4 */
long unsigned int raw; /* 8 8 */
}; /* 8 8 */
s32 off; /* 16 4 */
u32 id; /* 20 4 */
u32 ref_obj_id; /* 24 4 */
/* XXX 4 bytes hole, try to pack */
struct tnum var_off; /* 32 16 */
s64 smin_value; /* 48 8 */
s64 smax_value; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
u64 umin_value; /* 64 8 */
u64 umax_value; /* 72 8 */
s32 s32_min_value; /* 80 4 */
s32 s32_max_value; /* 84 4 */
u32 u32_min_value; /* 88 4 */
u32 u32_max_value; /* 92 4 */
struct bpf_reg_state * parent; /* 96 8 */
u32 frameno; /* 104 4 */
s32 subreg_def; /* 108 4 */
enum bpf_reg_liveness live; /* 112 4 */
bool precise; /* 116 1 */
/* size: 120, cachelines: 2, members: 19 */
/* sum members: 109, holes: 2, sum holes: 8 */
/* padding: 3 */
/* last cacheline: 56 bytes */
};
And with BTF pointer AFTER:
struct bpf_reg_state {
enum bpf_reg_type type; /* 0 4 */
s32 off; /* 4 4 */
union {
int range; /* 8 4 */
struct bpf_map * map_ptr; /* 8 8 */
struct {
struct btf * btf; /* 8 8 */
u32 btf_id; /* 16 4 */
}; /* 8 16 */
u32 mem_size; /* 8 4 */
struct {
long unsigned int raw1; /* 8 8 */
long unsigned int raw2; /* 16 8 */
} raw; /* 8 16 */
}; /* 8 16 */
u32 id; /* 24 4 */
u32 ref_obj_id; /* 28 4 */
struct tnum var_off; /* 32 16 */
s64 smin_value; /* 48 8 */
s64 smax_value; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
u64 umin_value; /* 64 8 */
u64 umax_value; /* 72 8 */
s32 s32_min_value; /* 80 4 */
s32 s32_max_value; /* 84 4 */
u32 u32_min_value; /* 88 4 */
u32 u32_max_value; /* 92 4 */
struct bpf_reg_state * parent; /* 96 8 */
u32 frameno; /* 104 4 */
s32 subreg_def; /* 108 4 */
enum bpf_reg_liveness live; /* 112 4 */
bool precise; /* 116 1 */
/* size: 120, cachelines: 2, members: 19 */
/* padding: 3 */
/* last cacheline: 56 bytes */
};
No more holes, but the same overall size. Does that work?
>
> >
> > 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;
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier
2020-11-30 23:04 ` Andrii Nakryiko
@ 2020-12-01 1:18 ` Alexei Starovoitov
0 siblings, 0 replies; 14+ messages in thread
From: Alexei Starovoitov @ 2020-12-01 1:18 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Andrii Nakryiko, bpf, Networking, Alexei Starovoitov,
Daniel Borkmann, Kernel Team
On Mon, Nov 30, 2020 at 3:04 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> No more holes, but the same overall size. Does that work?
Thanks. That's a good idea.
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2020-12-01 1:19 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-21 2:46 [PATCH bpf-next 0/7] Add kernel modules support for tracing BPF program attachments Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 1/7] bpf: remove hard-coded btf_vmlinux assumption from BPF verifier Andrii Nakryiko
2020-11-29 1:56 ` Alexei Starovoitov
2020-11-30 23:04 ` Andrii Nakryiko
2020-12-01 1:18 ` Alexei Starovoitov
2020-11-21 2:46 ` [PATCH bpf-next 2/7] bpf: allow to specify kernel module BTFs when attaching BPF programs Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 3/7] libbpf: factor out low-level BPF program loading helper Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 4/7] libbpf: support attachment of BPF tracing programs to kernel modules Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 5/7] selftests/bpf: add tp_btf CO-RE reloc test for modules Andrii Nakryiko
2020-11-29 1:59 ` Alexei Starovoitov
2020-11-30 22:52 ` Andrii Nakryiko
2020-11-30 22:55 ` Alexei Starovoitov
2020-11-21 2:46 ` [PATCH bpf-next 6/7] selftests/bpf: make BPF sidecar traceable function global Andrii Nakryiko
2020-11-21 2:46 ` [PATCH bpf-next 7/7] selftests/bpf: add fentry/fexit/fmod_ret selftest for kernel module Andrii Nakryiko
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