* [PATCH bpf-next v6 01/10] bpf: change prototype for stack_map_get_build_id_offset
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 02/10] bpf: add bpf_get_stack helper Yonghong Song
` (8 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
This patch didn't incur functionality change. The function prototype
got changed so that the same function can be reused later.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
kernel/bpf/stackmap.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 57eeb12..04f6ec1 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -262,16 +262,11 @@ static int stack_map_get_build_id(struct vm_area_struct *vma,
return ret;
}
-static void stack_map_get_build_id_offset(struct bpf_map *map,
- struct stack_map_bucket *bucket,
+static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
u64 *ips, u32 trace_nr, bool user)
{
int i;
struct vm_area_struct *vma;
- struct bpf_stack_build_id *id_offs;
-
- bucket->nr = trace_nr;
- id_offs = (struct bpf_stack_build_id *)bucket->data;
/*
* We cannot do up_read() in nmi context, so build_id lookup is
@@ -361,8 +356,10 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map,
pcpu_freelist_pop(&smap->freelist);
if (unlikely(!new_bucket))
return -ENOMEM;
- stack_map_get_build_id_offset(map, new_bucket, ips,
- trace_nr, user);
+ new_bucket->nr = trace_nr;
+ stack_map_get_build_id_offset(
+ (struct bpf_stack_build_id *)new_bucket->data,
+ ips, trace_nr, user);
trace_len = trace_nr * sizeof(struct bpf_stack_build_id);
if (hash_matches && bucket->nr == trace_nr &&
memcmp(bucket->data, new_bucket->data, trace_len) == 0) {
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 02/10] bpf: add bpf_get_stack helper
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 01/10] bpf: change prototype for stack_map_get_build_id_offset Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-25 9:00 ` Daniel Borkmann
2018-04-23 21:27 ` [PATCH bpf-next v6 03/10] bpf/verifier: refine retval R0 state for " Yonghong Song
` (7 subsequent siblings)
9 siblings, 1 reply; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
Currently, stackmap and bpf_get_stackid helper are provided
for bpf program to get the stack trace. This approach has
a limitation though. If two stack traces have the same hash,
only one will get stored in the stackmap table,
so some stack traces are missing from user perspective.
This patch implements a new helper, bpf_get_stack, will
send stack traces directly to bpf program. The bpf program
is able to see all stack traces, and then can do in-kernel
processing or send stack traces to user space through
shared map or bpf_perf_event_output.
Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
include/linux/bpf.h | 1 +
include/linux/filter.h | 3 ++-
include/uapi/linux/bpf.h | 19 ++++++++++++--
kernel/bpf/core.c | 5 ++++
kernel/bpf/stackmap.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++
kernel/bpf/syscall.c | 10 ++++++++
kernel/bpf/verifier.c | 3 +++
kernel/trace/bpf_trace.c | 50 +++++++++++++++++++++++++++++++++++-
8 files changed, 154 insertions(+), 4 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index ee5275e..2c520b4 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -690,6 +690,7 @@ extern const struct bpf_func_proto bpf_get_current_comm_proto;
extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
extern const struct bpf_func_proto bpf_get_stackid_proto;
+extern const struct bpf_func_proto bpf_get_stack_proto;
extern const struct bpf_func_proto bpf_sock_map_update_proto;
/* Shared helpers among cBPF and eBPF. */
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 4da8b23..044d30e 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -468,7 +468,8 @@ struct bpf_prog {
dst_needed:1, /* Do we need dst entry? */
blinded:1, /* Was blinded */
is_func:1, /* program is a bpf function */
- kprobe_override:1; /* Do we override a kprobe? */
+ kprobe_override:1, /* Do we override a kprobe? */
+ need_callchain_buf:1; /* Needs callchain buffer? */
enum bpf_prog_type type; /* Type of BPF program */
enum bpf_attach_type expected_attach_type; /* For some prog types */
u32 len; /* Number of filter blocks */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c8383a2..470f3a2 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -529,6 +529,17 @@ union bpf_attr {
* other bits - reserved
* Return: >= 0 stackid on success or negative error
*
+ * int bpf_get_stack(ctx, buf, size, flags)
+ * walk user or kernel stack and store the ips in buf
+ * @ctx: struct pt_regs*
+ * @buf: user buffer to fill stack
+ * @size: the buf size
+ * @flags: bits 0-7 - numer of stack frames to skip
+ * bit 8 - collect user stack instead of kernel
+ * bit 11 - get build-id as well if user stack
+ * other bits - reserved
+ * Return: >= 0 size copied on success or negative error
+ *
* s64 bpf_csum_diff(from, from_size, to, to_size, seed)
* calculate csum diff
* @from: raw from buffer
@@ -841,7 +852,8 @@ union bpf_attr {
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind), \
- FN(xdp_adjust_tail),
+ FN(xdp_adjust_tail), \
+ FN(get_stack),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
@@ -875,11 +887,14 @@ enum bpf_func_id {
/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
#define BPF_F_TUNINFO_IPV6 (1ULL << 0)
-/* BPF_FUNC_get_stackid flags. */
+/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
#define BPF_F_SKIP_FIELD_MASK 0xffULL
#define BPF_F_USER_STACK (1ULL << 8)
+/* flags used by BPF_FUNC_get_stackid only. */
#define BPF_F_FAST_STACK_CMP (1ULL << 9)
#define BPF_F_REUSE_STACKID (1ULL << 10)
+/* flags used by BPF_FUNC_get_stack only. */
+#define BPF_F_USER_BUILD_ID (1ULL << 11)
/* BPF_FUNC_skb_set_tunnel_key flags. */
#define BPF_F_ZERO_CSUM_TX (1ULL << 1)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index d315b39..bf22eca 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -31,6 +31,7 @@
#include <linux/rbtree_latch.h>
#include <linux/kallsyms.h>
#include <linux/rcupdate.h>
+#include <linux/perf_event.h>
#include <asm/unaligned.h>
@@ -1709,6 +1710,10 @@ static void bpf_prog_free_deferred(struct work_struct *work)
aux = container_of(work, struct bpf_prog_aux, work);
if (bpf_prog_is_dev_bound(aux))
bpf_prog_offload_destroy(aux->prog);
+#ifdef CONFIG_PERF_EVENTS
+ if (aux->prog->need_callchain_buf)
+ put_callchain_buffers();
+#endif
for (i = 0; i < aux->func_cnt; i++)
bpf_jit_free(aux->func[i]);
if (aux->func_cnt) {
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 04f6ec1..4477cf6 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -402,6 +402,73 @@ const struct bpf_func_proto bpf_get_stackid_proto = {
.arg3_type = ARG_ANYTHING,
};
+BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size,
+ u64, flags)
+{
+ u32 init_nr, trace_nr, copy_len, elem_size, num_elem;
+ bool user_build_id = flags & BPF_F_USER_BUILD_ID;
+ u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
+ bool user = flags & BPF_F_USER_STACK;
+ struct perf_callchain_entry *trace;
+ bool kernel = !user;
+ int err = -EINVAL;
+ u64 *ips;
+
+ if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
+ BPF_F_USER_BUILD_ID)))
+ goto clear;
+ if (kernel && user_build_id)
+ goto clear;
+
+ elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id)
+ : sizeof(u64);
+ if (unlikely(size % elem_size))
+ goto clear;
+
+ num_elem = size / elem_size;
+ if (sysctl_perf_event_max_stack < num_elem)
+ init_nr = 0;
+ else
+ init_nr = sysctl_perf_event_max_stack - num_elem;
+ trace = get_perf_callchain(regs, init_nr, kernel, user,
+ sysctl_perf_event_max_stack, false, false);
+ if (unlikely(!trace))
+ goto err_fault;
+
+ trace_nr = trace->nr - init_nr;
+ if (trace_nr <= skip)
+ goto err_fault;
+
+ trace_nr -= skip;
+ trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem;
+ copy_len = trace_nr * elem_size;
+ ips = trace->ip + skip + init_nr;
+ if (user && user_build_id)
+ stack_map_get_build_id_offset(buf, ips, trace_nr, user);
+ else
+ memcpy(buf, ips, copy_len);
+
+ if (size > copy_len)
+ memset(buf + copy_len, 0, size - copy_len);
+ return copy_len;
+
+err_fault:
+ err = -EFAULT;
+clear:
+ memset(buf, 0, size);
+ return err;
+}
+
+const struct bpf_func_proto bpf_get_stack_proto = {
+ .func = bpf_get_stack,
+ .gpl_only = true,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg3_type = ARG_CONST_SIZE_OR_ZERO,
+ .arg4_type = ARG_ANYTHING,
+};
+
/* Called from eBPF program */
static void *stack_map_lookup_elem(struct bpf_map *map, void *key)
{
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index fe23dc5a..1ee71f6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1360,6 +1360,16 @@ static int bpf_prog_load(union bpf_attr *attr)
if (err)
goto free_used_maps;
+ if (prog->need_callchain_buf) {
+#ifdef CONFIG_PERF_EVENTS
+ err = get_callchain_buffers(sysctl_perf_event_max_stack);
+#else
+ err = -ENOTSUPP;
+#endif
+ if (err)
+ goto free_used_maps;
+ }
+
err = bpf_prog_new_fd(prog);
if (err < 0) {
/* failed to allocate fd.
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5dd1dcb..aba9425 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2460,6 +2460,9 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
if (err)
return err;
+ if (func_id == BPF_FUNC_get_stack)
+ env->prog->need_callchain_buf = true;
+
if (changes_data)
clear_all_pkt_pointers(env);
return 0;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d88e96d..fe8476f 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -20,6 +20,7 @@
#include "trace.h"
u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
+u64 bpf_get_stack(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
/**
* trace_call_bpf - invoke BPF program
@@ -577,6 +578,8 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_perf_event_output_proto;
case BPF_FUNC_get_stackid:
return &bpf_get_stackid_proto;
+ case BPF_FUNC_get_stack:
+ return &bpf_get_stack_proto;
case BPF_FUNC_perf_event_read_value:
return &bpf_perf_event_read_value_proto;
#ifdef CONFIG_BPF_KPROBE_OVERRIDE
@@ -664,6 +667,25 @@ static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
.arg3_type = ARG_ANYTHING,
};
+BPF_CALL_4(bpf_get_stack_tp, void *, tp_buff, void *, buf, u32, size,
+ u64, flags)
+{
+ struct pt_regs *regs = *(struct pt_regs **)tp_buff;
+
+ return bpf_get_stack((unsigned long) regs, (unsigned long) buf,
+ (unsigned long) size, flags, 0);
+}
+
+static const struct bpf_func_proto bpf_get_stack_proto_tp = {
+ .func = bpf_get_stack_tp,
+ .gpl_only = true,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg3_type = ARG_CONST_SIZE_OR_ZERO,
+ .arg4_type = ARG_ANYTHING,
+};
+
static const struct bpf_func_proto *
tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
@@ -672,6 +694,8 @@ tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_perf_event_output_proto_tp;
case BPF_FUNC_get_stackid:
return &bpf_get_stackid_proto_tp;
+ case BPF_FUNC_get_stack:
+ return &bpf_get_stack_proto_tp;
default:
return tracing_func_proto(func_id, prog);
}
@@ -734,6 +758,8 @@ pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_perf_event_output_proto_tp;
case BPF_FUNC_get_stackid:
return &bpf_get_stackid_proto_tp;
+ case BPF_FUNC_get_stack:
+ return &bpf_get_stack_proto_tp;
case BPF_FUNC_perf_prog_read_value:
return &bpf_perf_prog_read_value_proto;
default:
@@ -744,7 +770,7 @@ pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
/*
* bpf_raw_tp_regs are separate from bpf_pt_regs used from skb/xdp
* to avoid potential recursive reuse issue when/if tracepoints are added
- * inside bpf_*_event_output and/or bpf_get_stack_id
+ * inside bpf_*_event_output, bpf_get_stackid and/or bpf_get_stack
*/
static DEFINE_PER_CPU(struct pt_regs, bpf_raw_tp_regs);
BPF_CALL_5(bpf_perf_event_output_raw_tp, struct bpf_raw_tracepoint_args *, args,
@@ -787,6 +813,26 @@ static const struct bpf_func_proto bpf_get_stackid_proto_raw_tp = {
.arg3_type = ARG_ANYTHING,
};
+BPF_CALL_4(bpf_get_stack_raw_tp, struct bpf_raw_tracepoint_args *, args,
+ void *, buf, u32, size, u64, flags)
+{
+ struct pt_regs *regs = this_cpu_ptr(&bpf_raw_tp_regs);
+
+ perf_fetch_caller_regs(regs);
+ return bpf_get_stack((unsigned long) regs, (unsigned long) buf,
+ (unsigned long) size, flags, 0);
+}
+
+static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = {
+ .func = bpf_get_stack_raw_tp,
+ .gpl_only = true,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_PTR_TO_MEM,
+ .arg3_type = ARG_CONST_SIZE_OR_ZERO,
+ .arg4_type = ARG_ANYTHING,
+};
+
static const struct bpf_func_proto *
raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
@@ -795,6 +841,8 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_perf_event_output_proto_raw_tp;
case BPF_FUNC_get_stackid:
return &bpf_get_stackid_proto_raw_tp;
+ case BPF_FUNC_get_stack:
+ return &bpf_get_stack_proto_raw_tp;
default:
return tracing_func_proto(func_id, prog);
}
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [PATCH bpf-next v6 02/10] bpf: add bpf_get_stack helper
2018-04-23 21:27 ` [PATCH bpf-next v6 02/10] bpf: add bpf_get_stack helper Yonghong Song
@ 2018-04-25 9:00 ` Daniel Borkmann
2018-04-25 16:44 ` Yonghong Song
0 siblings, 1 reply; 13+ messages in thread
From: Daniel Borkmann @ 2018-04-25 9:00 UTC (permalink / raw)
To: Yonghong Song, ast, netdev, ecree; +Cc: kernel-team
On 04/23/2018 11:27 PM, Yonghong Song wrote:
> Currently, stackmap and bpf_get_stackid helper are provided
> for bpf program to get the stack trace. This approach has
> a limitation though. If two stack traces have the same hash,
> only one will get stored in the stackmap table,
> so some stack traces are missing from user perspective.
>
> This patch implements a new helper, bpf_get_stack, will
> send stack traces directly to bpf program. The bpf program
> is able to see all stack traces, and then can do in-kernel
> processing or send stack traces to user space through
> shared map or bpf_perf_event_output.
>
> Acked-by: Alexei Starovoitov <ast@fb.com>
> Signed-off-by: Yonghong Song <yhs@fb.com>
[...]
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index d315b39..bf22eca 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -31,6 +31,7 @@
> #include <linux/rbtree_latch.h>
> #include <linux/kallsyms.h>
> #include <linux/rcupdate.h>
> +#include <linux/perf_event.h>
>
> #include <asm/unaligned.h>
>
> @@ -1709,6 +1710,10 @@ static void bpf_prog_free_deferred(struct work_struct *work)
> aux = container_of(work, struct bpf_prog_aux, work);
> if (bpf_prog_is_dev_bound(aux))
> bpf_prog_offload_destroy(aux->prog);
> +#ifdef CONFIG_PERF_EVENTS
> + if (aux->prog->need_callchain_buf)
> + put_callchain_buffers();
> +#endif
> for (i = 0; i < aux->func_cnt; i++)
> bpf_jit_free(aux->func[i]);
> if (aux->func_cnt) {
[...]
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index fe23dc5a..1ee71f6 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -1360,6 +1360,16 @@ static int bpf_prog_load(union bpf_attr *attr)
> if (err)
> goto free_used_maps;
>
> + if (prog->need_callchain_buf) {
> +#ifdef CONFIG_PERF_EVENTS
> + err = get_callchain_buffers(sysctl_perf_event_max_stack);
> +#else
> + err = -ENOTSUPP;
> +#endif
> + if (err)
> + goto free_used_maps;
> + }
> +
> err = bpf_prog_new_fd(prog);
> if (err < 0) {
> /* failed to allocate fd.
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 5dd1dcb..aba9425 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -2460,6 +2460,9 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
> if (err)
> return err;
>
> + if (func_id == BPF_FUNC_get_stack)
> + env->prog->need_callchain_buf = true;
> +
> if (changes_data)
> clear_all_pkt_pointers(env);
> return 0;
The above three hunks will cause a use-after-free on the perf callchain buffers.
In check_helper_call() you mark the prog with need_callchain_buf, where the
program hasn't fully completed verification phase yet, meaning some buggy prog
will still bail out.
However, you do the get_callchain_buffers() at a much later phase, so when you
bail out with error from bpf_check(), you take the free_used_maps error path
which calls bpf_prog_free().
The latter calls into bpf_prog_free_deferred() where you do the put_callchain_buffers()
since the need_callchain_buf is marked, but without prior get_callchain_buffers().
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH bpf-next v6 02/10] bpf: add bpf_get_stack helper
2018-04-25 9:00 ` Daniel Borkmann
@ 2018-04-25 16:44 ` Yonghong Song
0 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-25 16:44 UTC (permalink / raw)
To: Daniel Borkmann, ast, netdev, ecree; +Cc: kernel-team
On 4/25/18 2:00 AM, Daniel Borkmann wrote:
> On 04/23/2018 11:27 PM, Yonghong Song wrote:
>> Currently, stackmap and bpf_get_stackid helper are provided
>> for bpf program to get the stack trace. This approach has
>> a limitation though. If two stack traces have the same hash,
>> only one will get stored in the stackmap table,
>> so some stack traces are missing from user perspective.
>>
>> This patch implements a new helper, bpf_get_stack, will
>> send stack traces directly to bpf program. The bpf program
>> is able to see all stack traces, and then can do in-kernel
>> processing or send stack traces to user space through
>> shared map or bpf_perf_event_output.
>>
>> Acked-by: Alexei Starovoitov <ast@fb.com>
>> Signed-off-by: Yonghong Song <yhs@fb.com>
> [...]
>> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
>> index d315b39..bf22eca 100644
>> --- a/kernel/bpf/core.c
>> +++ b/kernel/bpf/core.c
>> @@ -31,6 +31,7 @@
>> #include <linux/rbtree_latch.h>
>> #include <linux/kallsyms.h>
>> #include <linux/rcupdate.h>
>> +#include <linux/perf_event.h>
>>
>> #include <asm/unaligned.h>
>>
>> @@ -1709,6 +1710,10 @@ static void bpf_prog_free_deferred(struct work_struct *work)
>> aux = container_of(work, struct bpf_prog_aux, work);
>> if (bpf_prog_is_dev_bound(aux))
>> bpf_prog_offload_destroy(aux->prog);
>> +#ifdef CONFIG_PERF_EVENTS
>> + if (aux->prog->need_callchain_buf)
>> + put_callchain_buffers();
>> +#endif
>> for (i = 0; i < aux->func_cnt; i++)
>> bpf_jit_free(aux->func[i]);
>> if (aux->func_cnt) {
> [...]
>> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
>> index fe23dc5a..1ee71f6 100644
>> --- a/kernel/bpf/syscall.c
>> +++ b/kernel/bpf/syscall.c
>> @@ -1360,6 +1360,16 @@ static int bpf_prog_load(union bpf_attr *attr)
>> if (err)
>> goto free_used_maps;
>>
>> + if (prog->need_callchain_buf) {
>> +#ifdef CONFIG_PERF_EVENTS
>> + err = get_callchain_buffers(sysctl_perf_event_max_stack);
>> +#else
>> + err = -ENOTSUPP;
>> +#endif
>> + if (err)
>> + goto free_used_maps;
>> + }
>> +
>> err = bpf_prog_new_fd(prog);
>> if (err < 0) {
>> /* failed to allocate fd.
>> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
>> index 5dd1dcb..aba9425 100644
>> --- a/kernel/bpf/verifier.c
>> +++ b/kernel/bpf/verifier.c
>> @@ -2460,6 +2460,9 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
>> if (err)
>> return err;
>>
>> + if (func_id == BPF_FUNC_get_stack)
>> + env->prog->need_callchain_buf = true;
>> +
>> if (changes_data)
>> clear_all_pkt_pointers(env);
>> return 0;
>
> The above three hunks will cause a use-after-free on the perf callchain buffers.
>
> In check_helper_call() you mark the prog with need_callchain_buf, where the
> program hasn't fully completed verification phase yet, meaning some buggy prog
> will still bail out.
>
> However, you do the get_callchain_buffers() at a much later phase, so when you
> bail out with error from bpf_check(), you take the free_used_maps error path
> which calls bpf_prog_free().
>
> The latter calls into bpf_prog_free_deferred() where you do the put_callchain_buffers()
> since the need_callchain_buf is marked, but without prior get_callchain_buffers().
Thanks for catching this! Yes, this is a real issue. I will fix it and
respin.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH bpf-next v6 03/10] bpf/verifier: refine retval R0 state for bpf_get_stack helper
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 01/10] bpf: change prototype for stack_map_get_build_id_offset Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 02/10] bpf: add bpf_get_stack helper Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 04/10] bpf: remove never-hit branches in verifier adjust_scalar_min_max_vals Yonghong Song
` (6 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
The special property of return values for helpers bpf_get_stack
and bpf_probe_read_str are captured in verifier.
Both helpers return a negative error code or
a length, which is equal to or smaller than the buffer
size argument. This additional information in the
verifier can avoid the condition such as "retval > bufsize"
in the bpf program. For example, for the code blow,
usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK);
if (usize < 0 || usize > max_len)
return 0;
The verifier may have the following errors:
52: (85) call bpf_get_stack#65
R0=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R1_w=ctx(id=0,off=0,imm=0)
R2_w=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R3_w=inv800 R4_w=inv256
R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0)
R9_w=inv800 R10=fp0,call_-1
53: (bf) r8 = r0
54: (bf) r1 = r8
55: (67) r1 <<= 32
56: (bf) r2 = r1
57: (77) r2 >>= 32
58: (25) if r2 > 0x31f goto pc+33
R0=inv(id=0) R1=inv(id=0,smax_value=9223372032559808512,
umax_value=18446744069414584320,
var_off=(0x0; 0xffffffff00000000))
R2=inv(id=0,umax_value=799,var_off=(0x0; 0x3ff))
R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0)
R8=inv(id=0) R9=inv800 R10=fp0,call_-1
59: (1f) r9 -= r8
60: (c7) r1 s>>= 32
61: (bf) r2 = r7
62: (0f) r2 += r1
math between map_value pointer and register with unbounded
min value is not allowed
The failure is due to llvm compiler optimization where register "r2",
which is a copy of "r1", is tested for condition while later on "r1"
is used for map_ptr operation. The verifier is not able to track such
inst sequence effectively.
Without the "usize > max_len" condition, there is no llvm optimization
and the below generated code passed verifier:
52: (85) call bpf_get_stack#65
R0=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R1_w=ctx(id=0,off=0,imm=0)
R2_w=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R3_w=inv800 R4_w=inv256
R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0)
R9_w=inv800 R10=fp0,call_-1
53: (b7) r1 = 0
54: (bf) r8 = r0
55: (67) r8 <<= 32
56: (c7) r8 s>>= 32
57: (6d) if r1 s> r8 goto pc+24
R0=inv(id=0,umax_value=800,var_off=(0x0; 0x3ff))
R1=inv0 R6=ctx(id=0,off=0,imm=0)
R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0)
R8=inv(id=0,umax_value=800,var_off=(0x0; 0x3ff)) R9=inv800
R10=fp0,call_-1
58: (bf) r2 = r7
59: (0f) r2 += r8
60: (1f) r9 -= r8
61: (bf) r1 = r6
Signed-off-by: Yonghong Song <yhs@fb.com>
---
kernel/bpf/verifier.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index aba9425..d531119 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -164,6 +164,8 @@ struct bpf_call_arg_meta {
bool pkt_access;
int regno;
int access_size;
+ s64 msize_smax_value;
+ u64 msize_umax_value;
};
static DEFINE_MUTEX(bpf_verifier_lock);
@@ -1994,6 +1996,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
} else if (arg_type_is_mem_size(arg_type)) {
bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO);
+ /* remember the mem_size which may be used later
+ * to refine return values.
+ */
+ meta->msize_smax_value = reg->smax_value;
+ meta->msize_umax_value = reg->umax_value;
+
/* The register is SCALAR_VALUE; the access check
* happens using its boundaries.
*/
@@ -2333,6 +2341,23 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
return 0;
}
+static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
+ int func_id,
+ struct bpf_call_arg_meta *meta)
+{
+ struct bpf_reg_state *ret_reg = ®s[BPF_REG_0];
+
+ if (ret_type != RET_INTEGER ||
+ (func_id != BPF_FUNC_get_stack &&
+ func_id != BPF_FUNC_probe_read_str))
+ return;
+
+ ret_reg->smax_value = meta->msize_smax_value;
+ ret_reg->umax_value = meta->msize_umax_value;
+ __reg_deduce_bounds(ret_reg);
+ __reg_bound_offset(ret_reg);
+}
+
static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
{
const struct bpf_func_proto *fn = NULL;
@@ -2456,6 +2481,8 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
return -EINVAL;
}
+ do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
+
err = check_map_func_compatibility(env, meta.map_ptr, func_id);
if (err)
return err;
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 04/10] bpf: remove never-hit branches in verifier adjust_scalar_min_max_vals
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
` (2 preceding siblings ...)
2018-04-23 21:27 ` [PATCH bpf-next v6 03/10] bpf/verifier: refine retval R0 state for " Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 05/10] bpf/verifier: improve register value range tracking with ARSH Yonghong Song
` (5 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
In verifier function adjust_scalar_min_max_vals,
when src_known is false and the opcode is BPF_LSH/BPF_RSH,
early return will happen in the function. So remove
the branch in handling BPF_LSH/BPF_RSH when src_known is false.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
kernel/bpf/verifier.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d531119..217d92a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2934,10 +2934,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
dst_reg->umin_value <<= umin_val;
dst_reg->umax_value <<= umax_val;
}
- if (src_known)
- dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
- else
- dst_reg->var_off = tnum_lshift(tnum_unknown, umin_val);
+ dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
/* We may learn something more from the var_off */
__update_reg_bounds(dst_reg);
break;
@@ -2965,11 +2962,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
*/
dst_reg->smin_value = S64_MIN;
dst_reg->smax_value = S64_MAX;
- if (src_known)
- dst_reg->var_off = tnum_rshift(dst_reg->var_off,
- umin_val);
- else
- dst_reg->var_off = tnum_rshift(tnum_unknown, umin_val);
+ dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);
dst_reg->umin_value >>= umax_val;
dst_reg->umax_value >>= umin_val;
/* We may learn something more from the var_off */
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 05/10] bpf/verifier: improve register value range tracking with ARSH
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
` (3 preceding siblings ...)
2018-04-23 21:27 ` [PATCH bpf-next v6 04/10] bpf: remove never-hit branches in verifier adjust_scalar_min_max_vals Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 06/10] tools/bpf: add bpf_get_stack helper to tools headers Yonghong Song
` (4 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
When helpers like bpf_get_stack returns an int value
and later on used for arithmetic computation, the LSH and ARSH
operations are often required to get proper sign extension into
64-bit. For example, without this patch:
54: R0=inv(id=0,umax_value=800)
54: (bf) r8 = r0
55: R0=inv(id=0,umax_value=800) R8_w=inv(id=0,umax_value=800)
55: (67) r8 <<= 32
56: R8_w=inv(id=0,umax_value=3435973836800,var_off=(0x0; 0x3ff00000000))
56: (c7) r8 s>>= 32
57: R8=inv(id=0)
With this patch:
54: R0=inv(id=0,umax_value=800)
54: (bf) r8 = r0
55: R0=inv(id=0,umax_value=800) R8_w=inv(id=0,umax_value=800)
55: (67) r8 <<= 32
56: R8_w=inv(id=0,umax_value=3435973836800,var_off=(0x0; 0x3ff00000000))
56: (c7) r8 s>>= 32
57: R8=inv(id=0, umax_value=800,var_off=(0x0; 0x3ff))
With better range of "R8", later on when "R8" is added to other register,
e.g., a map pointer or scalar-value register, the better register
range can be derived and verifier failure may be avoided.
In our later example,
......
usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK);
if (usize < 0)
return 0;
ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0);
......
Without improving ARSH value range tracking, the register representing
"max_len - usize" will have smin_value equal to S64_MIN and will be
rejected by verifier.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
include/linux/tnum.h | 4 +++-
kernel/bpf/tnum.c | 10 ++++++++++
kernel/bpf/verifier.c | 41 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 54 insertions(+), 1 deletion(-)
diff --git a/include/linux/tnum.h b/include/linux/tnum.h
index 0d2d3da..c7dc2b5 100644
--- a/include/linux/tnum.h
+++ b/include/linux/tnum.h
@@ -23,8 +23,10 @@ struct tnum tnum_range(u64 min, u64 max);
/* Arithmetic and logical ops */
/* Shift a tnum left (by a fixed shift) */
struct tnum tnum_lshift(struct tnum a, u8 shift);
-/* Shift a tnum right (by a fixed shift) */
+/* Shift (rsh) a tnum right (by a fixed shift) */
struct tnum tnum_rshift(struct tnum a, u8 shift);
+/* Shift (arsh) a tnum right (by a fixed min_shift) */
+struct tnum tnum_arshift(struct tnum a, u8 min_shift);
/* Add two tnums, return @a + @b */
struct tnum tnum_add(struct tnum a, struct tnum b);
/* Subtract two tnums, return @a - @b */
diff --git a/kernel/bpf/tnum.c b/kernel/bpf/tnum.c
index 1f4bf68..938d412 100644
--- a/kernel/bpf/tnum.c
+++ b/kernel/bpf/tnum.c
@@ -43,6 +43,16 @@ struct tnum tnum_rshift(struct tnum a, u8 shift)
return TNUM(a.value >> shift, a.mask >> shift);
}
+struct tnum tnum_arshift(struct tnum a, u8 min_shift)
+{
+ /* if a.value is negative, arithmetic shifting by minimum shift
+ * will have larger negative offset compared to more shifting.
+ * If a.value is nonnegative, arithmetic shifting by minimum shift
+ * will have larger positive offset compare to more shifting.
+ */
+ return TNUM((s64)a.value >> min_shift, (s64)a.mask >> min_shift);
+}
+
struct tnum tnum_add(struct tnum a, struct tnum b)
{
u64 sm, sv, sigma, chi, mu;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 217d92a..643923e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2968,6 +2968,47 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
/* We may learn something more from the var_off */
__update_reg_bounds(dst_reg);
break;
+ case BPF_ARSH:
+ if (umax_val >= insn_bitness) {
+ /* Shifts greater than 31 or 63 are undefined.
+ * This includes shifts by a negative number.
+ */
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ break;
+ }
+
+ /* BPF_ARSH is an arithmetic shift. The new range of
+ * smin_value and smax_value should take the sign
+ * into consideration.
+ *
+ * For example, if smin_value = -16, umin_val = 0
+ * and umax_val = 2, the new smin_value should be
+ * -16 >> 0 = -16 since -16 >> 2 = -4.
+ * If smin_value = 16, umin_val = 0 and umax_val = 2,
+ * the new smin_value should be 16 >> 2 = 4.
+ *
+ * Now suppose smax_value = -4, umin_val = 0 and
+ * umax_val = 2, the new smax_value should be
+ * -4 >> 2 = -1. If smax_value = 32 with the same
+ * umin_val/umax_val, the new smax_value should remain 32.
+ */
+ if (dst_reg->smin_value < 0)
+ dst_reg->smin_value >>= umin_val;
+ else
+ dst_reg->smin_value >>= umax_val;
+ if (dst_reg->smax_value < 0)
+ dst_reg->smax_value >>= umax_val;
+ else
+ dst_reg->smax_value >>= umin_val;
+ dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val);
+
+ /* blow away the dst_reg umin_value/umax_value and rely on
+ * dst_reg var_off to refine the result.
+ */
+ dst_reg->umin_value = 0;
+ dst_reg->umax_value = U64_MAX;
+ __update_reg_bounds(dst_reg);
+ break;
default:
mark_reg_unknown(env, regs, insn->dst_reg);
break;
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 06/10] tools/bpf: add bpf_get_stack helper to tools headers
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
` (4 preceding siblings ...)
2018-04-23 21:27 ` [PATCH bpf-next v6 05/10] bpf/verifier: improve register value range tracking with ARSH Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 07/10] samples/bpf: move common-purpose trace functions to selftests Yonghong Song
` (3 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
The tools header file bpf.h is synced with kernel uapi bpf.h.
The new helper is also added to bpf_helpers.h.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
tools/include/uapi/linux/bpf.h | 19 +++++++++++++++++--
tools/testing/selftests/bpf/bpf_helpers.h | 3 ++-
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7f7fbb9..116eb5f 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -529,6 +529,17 @@ union bpf_attr {
* other bits - reserved
* Return: >= 0 stackid on success or negative error
*
+ * int bpf_get_stack(ctx, buf, size, flags)
+ * walk user or kernel stack and store the ips in buf
+ * @ctx: struct pt_regs*
+ * @buf: user buffer to fill stack
+ * @size: the buf size
+ * @flags: bits 0-7 - numer of stack frames to skip
+ * bit 8 - collect user stack instead of kernel
+ * bit 11 - get build-id as well if user stack
+ * other bits - reserved
+ * Return: >= 0 size copied on success or negative error
+ *
* s64 bpf_csum_diff(from, from_size, to, to_size, seed)
* calculate csum diff
* @from: raw from buffer
@@ -841,7 +852,8 @@ union bpf_attr {
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind), \
- FN(xdp_adjust_tail),
+ FN(xdp_adjust_tail), \
+ FN(get_stack),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
@@ -875,11 +887,14 @@ enum bpf_func_id {
/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
#define BPF_F_TUNINFO_IPV6 (1ULL << 0)
-/* BPF_FUNC_get_stackid flags. */
+/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
#define BPF_F_SKIP_FIELD_MASK 0xffULL
#define BPF_F_USER_STACK (1ULL << 8)
+/* flags used by BPF_FUNC_get_stackid only. */
#define BPF_F_FAST_STACK_CMP (1ULL << 9)
#define BPF_F_REUSE_STACKID (1ULL << 10)
+/* flags used by BPF_FUNC_get_stack only. */
+#define BPF_F_USER_BUILD_ID (1ULL << 11)
/* BPF_FUNC_skb_set_tunnel_key flags. */
#define BPF_F_ZERO_CSUM_TX (1ULL << 1)
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 9271576..2d9d650 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -98,7 +98,8 @@ static int (*bpf_bind)(void *ctx, void *addr, int addr_len) =
(void *) BPF_FUNC_bind;
static int (*bpf_xdp_adjust_tail)(void *ctx, int offset) =
(void *) BPF_FUNC_xdp_adjust_tail;
-
+static int (*bpf_get_stack)(void *ctx, void *buf, int size, int flags) =
+ (void *) BPF_FUNC_get_stack;
/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 07/10] samples/bpf: move common-purpose trace functions to selftests
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
` (5 preceding siblings ...)
2018-04-23 21:27 ` [PATCH bpf-next v6 06/10] tools/bpf: add bpf_get_stack helper to tools headers Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 08/10] tools/bpf: add a verifier test case for bpf_get_stack helper and ARSH Yonghong Song
` (2 subsequent siblings)
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
There is no functionality change in this patch. The common-purpose
trace functions, including perf_event polling and ksym lookup,
are moved from trace_output_user.c and bpf_load.c to
selftests/bpf/trace_helpers.c so that these function can
be reused later in selftests.
Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
samples/bpf/Makefile | 11 +-
samples/bpf/bpf_load.c | 63 ----------
samples/bpf/bpf_load.h | 7 --
samples/bpf/offwaketime_user.c | 1 +
samples/bpf/sampleip_user.c | 1 +
samples/bpf/spintest_user.c | 1 +
samples/bpf/trace_event_user.c | 1 +
samples/bpf/trace_output_user.c | 125 +++----------------
tools/testing/selftests/bpf/trace_helpers.c | 186 ++++++++++++++++++++++++++++
tools/testing/selftests/bpf/trace_helpers.h | 24 ++++
10 files changed, 238 insertions(+), 182 deletions(-)
create mode 100644 tools/testing/selftests/bpf/trace_helpers.c
create mode 100644 tools/testing/selftests/bpf/trace_helpers.h
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index aa8c392..d36444c 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -49,6 +49,7 @@ hostprogs-y += xdp_adjust_tail
# Libbpf dependencies
LIBBPF := ../../tools/lib/bpf/bpf.o ../../tools/lib/bpf/nlattr.o
CGROUP_HELPERS := ../../tools/testing/selftests/bpf/cgroup_helpers.o
+TRACE_HELPERS := ../../tools/testing/selftests/bpf/trace_helpers.o
test_lru_dist-objs := test_lru_dist.o $(LIBBPF)
sock_example-objs := sock_example.o $(LIBBPF)
@@ -65,10 +66,10 @@ tracex6-objs := bpf_load.o $(LIBBPF) tracex6_user.o
tracex7-objs := bpf_load.o $(LIBBPF) tracex7_user.o
load_sock_ops-objs := bpf_load.o $(LIBBPF) load_sock_ops.o
test_probe_write_user-objs := bpf_load.o $(LIBBPF) test_probe_write_user_user.o
-trace_output-objs := bpf_load.o $(LIBBPF) trace_output_user.o
+trace_output-objs := bpf_load.o $(LIBBPF) trace_output_user.o $(TRACE_HELPERS)
lathist-objs := bpf_load.o $(LIBBPF) lathist_user.o
-offwaketime-objs := bpf_load.o $(LIBBPF) offwaketime_user.o
-spintest-objs := bpf_load.o $(LIBBPF) spintest_user.o
+offwaketime-objs := bpf_load.o $(LIBBPF) offwaketime_user.o $(TRACE_HELPERS)
+spintest-objs := bpf_load.o $(LIBBPF) spintest_user.o $(TRACE_HELPERS)
map_perf_test-objs := bpf_load.o $(LIBBPF) map_perf_test_user.o
test_overhead-objs := bpf_load.o $(LIBBPF) test_overhead_user.o
test_cgrp2_array_pin-objs := $(LIBBPF) test_cgrp2_array_pin.o
@@ -82,8 +83,8 @@ xdp2-objs := bpf_load.o $(LIBBPF) xdp1_user.o
xdp_router_ipv4-objs := bpf_load.o $(LIBBPF) xdp_router_ipv4_user.o
test_current_task_under_cgroup-objs := bpf_load.o $(LIBBPF) $(CGROUP_HELPERS) \
test_current_task_under_cgroup_user.o
-trace_event-objs := bpf_load.o $(LIBBPF) trace_event_user.o
-sampleip-objs := bpf_load.o $(LIBBPF) sampleip_user.o
+trace_event-objs := bpf_load.o $(LIBBPF) trace_event_user.o $(TRACE_HELPERS)
+sampleip-objs := bpf_load.o $(LIBBPF) sampleip_user.o $(TRACE_HELPERS)
tc_l2_redirect-objs := bpf_load.o $(LIBBPF) tc_l2_redirect_user.o
lwt_len_hist-objs := bpf_load.o $(LIBBPF) lwt_len_hist_user.o
xdp_tx_iptunnel-objs := bpf_load.o $(LIBBPF) xdp_tx_iptunnel_user.o
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index bebe418..529972e 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -650,66 +650,3 @@ void read_trace_pipe(void)
}
}
}
-
-#define MAX_SYMS 300000
-static struct ksym syms[MAX_SYMS];
-static int sym_cnt;
-
-static int ksym_cmp(const void *p1, const void *p2)
-{
- return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
-}
-
-int load_kallsyms(void)
-{
- FILE *f = fopen("/proc/kallsyms", "r");
- char func[256], buf[256];
- char symbol;
- void *addr;
- int i = 0;
-
- if (!f)
- return -ENOENT;
-
- while (!feof(f)) {
- if (!fgets(buf, sizeof(buf), f))
- break;
- if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
- break;
- if (!addr)
- continue;
- syms[i].addr = (long) addr;
- syms[i].name = strdup(func);
- i++;
- }
- sym_cnt = i;
- qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp);
- return 0;
-}
-
-struct ksym *ksym_search(long key)
-{
- int start = 0, end = sym_cnt;
- int result;
-
- while (start < end) {
- size_t mid = start + (end - start) / 2;
-
- result = key - syms[mid].addr;
- if (result < 0)
- end = mid;
- else if (result > 0)
- start = mid + 1;
- else
- return &syms[mid];
- }
-
- if (start >= 1 && syms[start - 1].addr < key &&
- key < syms[start].addr)
- /* valid ksym */
- return &syms[start - 1];
-
- /* out of range. return _stext */
- return &syms[0];
-}
-
diff --git a/samples/bpf/bpf_load.h b/samples/bpf/bpf_load.h
index 453c200..2c3d0b4 100644
--- a/samples/bpf/bpf_load.h
+++ b/samples/bpf/bpf_load.h
@@ -54,12 +54,5 @@ int load_bpf_file(char *path);
int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map);
void read_trace_pipe(void);
-struct ksym {
- long addr;
- char *name;
-};
-
-int load_kallsyms(void);
-struct ksym *ksym_search(long key);
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
#endif
diff --git a/samples/bpf/offwaketime_user.c b/samples/bpf/offwaketime_user.c
index 512f87a..f06063a 100644
--- a/samples/bpf/offwaketime_user.c
+++ b/samples/bpf/offwaketime_user.c
@@ -17,6 +17,7 @@
#include <sys/resource.h>
#include "libbpf.h"
#include "bpf_load.h"
+#include "trace_helpers.h"
#define PRINT_RAW_ADDR 0
diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
index 4ed690b..60c2b73 100644
--- a/samples/bpf/sampleip_user.c
+++ b/samples/bpf/sampleip_user.c
@@ -22,6 +22,7 @@
#include "libbpf.h"
#include "bpf_load.h"
#include "perf-sys.h"
+#include "trace_helpers.h"
#define DEFAULT_FREQ 99
#define DEFAULT_SECS 5
diff --git a/samples/bpf/spintest_user.c b/samples/bpf/spintest_user.c
index 3d73621..8d3e9cf 100644
--- a/samples/bpf/spintest_user.c
+++ b/samples/bpf/spintest_user.c
@@ -7,6 +7,7 @@
#include <sys/resource.h>
#include "libbpf.h"
#include "bpf_load.h"
+#include "trace_helpers.h"
int main(int ac, char **argv)
{
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
index 56f7a25..1fa1bec 100644
--- a/samples/bpf/trace_event_user.c
+++ b/samples/bpf/trace_event_user.c
@@ -21,6 +21,7 @@
#include "libbpf.h"
#include "bpf_load.h"
#include "perf-sys.h"
+#include "trace_helpers.h"
#define SAMPLE_FREQ 50
diff --git a/samples/bpf/trace_output_user.c b/samples/bpf/trace_output_user.c
index ccca1e3..cc4b383 100644
--- a/samples/bpf/trace_output_user.c
+++ b/samples/bpf/trace_output_user.c
@@ -21,100 +21,10 @@
#include "libbpf.h"
#include "bpf_load.h"
#include "perf-sys.h"
+#include "trace_helpers.h"
static int pmu_fd;
-int page_size;
-int page_cnt = 8;
-volatile struct perf_event_mmap_page *header;
-
-typedef void (*print_fn)(void *data, int size);
-
-static int perf_event_mmap(int fd)
-{
- void *base;
- int mmap_size;
-
- page_size = getpagesize();
- mmap_size = page_size * (page_cnt + 1);
-
- base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- if (base == MAP_FAILED) {
- printf("mmap err\n");
- return -1;
- }
-
- header = base;
- return 0;
-}
-
-static int perf_event_poll(int fd)
-{
- struct pollfd pfd = { .fd = fd, .events = POLLIN };
-
- return poll(&pfd, 1, 1000);
-}
-
-struct perf_event_sample {
- struct perf_event_header header;
- __u32 size;
- char data[];
-};
-
-static void perf_event_read(print_fn fn)
-{
- __u64 data_tail = header->data_tail;
- __u64 data_head = header->data_head;
- __u64 buffer_size = page_cnt * page_size;
- void *base, *begin, *end;
- char buf[256];
-
- asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
- if (data_head == data_tail)
- return;
-
- base = ((char *)header) + page_size;
-
- begin = base + data_tail % buffer_size;
- end = base + data_head % buffer_size;
-
- while (begin != end) {
- struct perf_event_sample *e;
-
- e = begin;
- if (begin + e->header.size > base + buffer_size) {
- long len = base + buffer_size - begin;
-
- assert(len < e->header.size);
- memcpy(buf, begin, len);
- memcpy(buf + len, base, e->header.size - len);
- e = (void *) buf;
- begin = base + e->header.size - len;
- } else if (begin + e->header.size == base + buffer_size) {
- begin = base;
- } else {
- begin += e->header.size;
- }
-
- if (e->header.type == PERF_RECORD_SAMPLE) {
- fn(e->data, e->size);
- } else if (e->header.type == PERF_RECORD_LOST) {
- struct {
- struct perf_event_header header;
- __u64 id;
- __u64 lost;
- } *lost = (void *) e;
- printf("lost %lld events\n", lost->lost);
- } else {
- printf("unknown event type=%d size=%d\n",
- e->header.type, e->header.size);
- }
- }
-
- __sync_synchronize(); /* smp_mb() */
- header->data_tail = data_head;
-}
-
static __u64 time_get_ns(void)
{
struct timespec ts;
@@ -127,7 +37,7 @@ static __u64 start_time;
#define MAX_CNT 100000ll
-static void print_bpf_output(void *data, int size)
+static int print_bpf_output(void *data, int size)
{
static __u64 cnt;
struct {
@@ -138,7 +48,7 @@ static void print_bpf_output(void *data, int size)
if (e->cookie != 0x12345678) {
printf("BUG pid %llx cookie %llx sized %d\n",
e->pid, e->cookie, size);
- kill(0, SIGINT);
+ return PERF_EVENT_ERROR;
}
cnt++;
@@ -146,8 +56,10 @@ static void print_bpf_output(void *data, int size)
if (cnt == MAX_CNT) {
printf("recv %lld events per sec\n",
MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
- kill(0, SIGINT);
+ return PERF_EVENT_DONE;
}
+
+ return PERF_EVENT_CONT;
}
static void test_bpf_perf_event(void)
@@ -166,10 +78,18 @@ static void test_bpf_perf_event(void)
ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
}
+static void exec_action(void)
+{
+ FILE *f;
+
+ f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
+ (void) f;
+}
+
int main(int argc, char **argv)
{
char filename[256];
- FILE *f;
+ int ret;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
@@ -180,17 +100,8 @@ int main(int argc, char **argv)
test_bpf_perf_event();
- if (perf_event_mmap(pmu_fd) < 0)
- return 1;
-
- f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
- (void) f;
-
start_time = time_get_ns();
- for (;;) {
- perf_event_poll(pmu_fd);
- perf_event_read(print_bpf_output);
- }
-
- return 0;
+ ret = perf_event_poller(pmu_fd, exec_action, print_bpf_output);
+ kill(0, SIGINT);
+ return ret;
}
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
new file mode 100644
index 0000000..00954e3
--- /dev/null
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <poll.h>
+#include <unistd.h>
+#include <linux/perf_event.h>
+#include <sys/mman.h>
+#include "trace_helpers.h"
+
+#define MAX_SYMS 300000
+static struct ksym syms[MAX_SYMS];
+static int sym_cnt;
+
+static int ksym_cmp(const void *p1, const void *p2)
+{
+ return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
+}
+
+int load_kallsyms(void)
+{
+ FILE *f = fopen("/proc/kallsyms", "r");
+ char func[256], buf[256];
+ char symbol;
+ void *addr;
+ int i = 0;
+
+ if (!f)
+ return -ENOENT;
+
+ while (!feof(f)) {
+ if (!fgets(buf, sizeof(buf), f))
+ break;
+ if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
+ break;
+ if (!addr)
+ continue;
+ syms[i].addr = (long) addr;
+ syms[i].name = strdup(func);
+ i++;
+ }
+ sym_cnt = i;
+ qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp);
+ return 0;
+}
+
+struct ksym *ksym_search(long key)
+{
+ int start = 0, end = sym_cnt;
+ int result;
+
+ while (start < end) {
+ size_t mid = start + (end - start) / 2;
+
+ result = key - syms[mid].addr;
+ if (result < 0)
+ end = mid;
+ else if (result > 0)
+ start = mid + 1;
+ else
+ return &syms[mid];
+ }
+
+ if (start >= 1 && syms[start - 1].addr < key &&
+ key < syms[start].addr)
+ /* valid ksym */
+ return &syms[start - 1];
+
+ /* out of range. return _stext */
+ return &syms[0];
+}
+
+static int page_size;
+static int page_cnt = 8;
+static volatile struct perf_event_mmap_page *header;
+
+static int perf_event_mmap(int fd)
+{
+ void *base;
+ int mmap_size;
+
+ page_size = getpagesize();
+ mmap_size = page_size * (page_cnt + 1);
+
+ base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ if (base == MAP_FAILED) {
+ printf("mmap err\n");
+ return -1;
+ }
+
+ header = base;
+ return 0;
+}
+
+static int perf_event_poll(int fd)
+{
+ struct pollfd pfd = { .fd = fd, .events = POLLIN };
+
+ return poll(&pfd, 1, 1000);
+}
+
+struct perf_event_sample {
+ struct perf_event_header header;
+ __u32 size;
+ char data[];
+};
+
+static int perf_event_read(perf_event_print_fn fn)
+{
+ __u64 data_tail = header->data_tail;
+ __u64 data_head = header->data_head;
+ __u64 buffer_size = page_cnt * page_size;
+ void *base, *begin, *end;
+ char buf[256];
+ int ret;
+
+ asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
+ if (data_head == data_tail)
+ return PERF_EVENT_CONT;
+
+ base = ((char *)header) + page_size;
+
+ begin = base + data_tail % buffer_size;
+ end = base + data_head % buffer_size;
+
+ while (begin != end) {
+ struct perf_event_sample *e;
+
+ e = begin;
+ if (begin + e->header.size > base + buffer_size) {
+ long len = base + buffer_size - begin;
+
+ assert(len < e->header.size);
+ memcpy(buf, begin, len);
+ memcpy(buf + len, base, e->header.size - len);
+ e = (void *) buf;
+ begin = base + e->header.size - len;
+ } else if (begin + e->header.size == base + buffer_size) {
+ begin = base;
+ } else {
+ begin += e->header.size;
+ }
+
+ if (e->header.type == PERF_RECORD_SAMPLE) {
+ ret = fn(e->data, e->size);
+ if (ret != PERF_EVENT_CONT)
+ return ret;
+ } else if (e->header.type == PERF_RECORD_LOST) {
+ struct {
+ struct perf_event_header header;
+ __u64 id;
+ __u64 lost;
+ } *lost = (void *) e;
+ printf("lost %lld events\n", lost->lost);
+ } else {
+ printf("unknown event type=%d size=%d\n",
+ e->header.type, e->header.size);
+ }
+ }
+
+ __sync_synchronize(); /* smp_mb() */
+ header->data_tail = data_head;
+ return PERF_EVENT_CONT;
+}
+
+int perf_event_poller(int fd, perf_event_exec_fn exec_fn,
+ perf_event_print_fn output_fn)
+{
+ int ret;
+
+ if (perf_event_mmap(fd) < 0)
+ return PERF_EVENT_ERROR;
+
+ exec_fn();
+
+ for (;;) {
+ perf_event_poll(fd);
+ ret = perf_event_read(output_fn);
+ if (ret != PERF_EVENT_CONT)
+ return ret;
+ }
+
+ return PERF_EVENT_DONE;
+}
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
new file mode 100644
index 0000000..8750778
--- /dev/null
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TRACE_HELPER_H
+#define __TRACE_HELPER_H
+
+struct ksym {
+ long addr;
+ char *name;
+};
+
+int load_kallsyms(void);
+struct ksym *ksym_search(long key);
+
+typedef void (*perf_event_exec_fn)(void);
+typedef int (*perf_event_print_fn)(void *data, int size);
+
+/* return code for perf_event_print_fn */
+#define PERF_EVENT_DONE 0
+#define PERF_EVENT_ERROR 1
+#define PERF_EVENT_CONT 2
+
+/* return PERF_EVENT_DONE or PERF_EVENT_ERROR */
+int perf_event_poller(int fd, perf_event_exec_fn exec_fn,
+ perf_event_print_fn output_fn);
+#endif
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 08/10] tools/bpf: add a verifier test case for bpf_get_stack helper and ARSH
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
` (6 preceding siblings ...)
2018-04-23 21:27 ` [PATCH bpf-next v6 07/10] samples/bpf: move common-purpose trace functions to selftests Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 09/10] tools/bpf: add a test for bpf_get_stack with raw tracepoint prog Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 10/10] tools/bpf: add a test for bpf_get_stack with " Yonghong Song
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
The test_verifier already has a few ARSH test cases.
This patch adds a new test case which takes advantage of newly
improved verifier behavior for bpf_get_stack and ARSH.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
tools/testing/selftests/bpf/test_verifier.c | 45 +++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 3e7718b..cd595ba 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -11423,6 +11423,51 @@ static struct bpf_test tests[] = {
.errstr = "BPF_XADD stores into R2 packet",
.prog_type = BPF_PROG_TYPE_XDP,
},
+ {
+ "bpf_get_stack return R0 within range",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 28),
+ BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
+ BPF_MOV64_IMM(BPF_REG_9, sizeof(struct test_val)),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
+ BPF_MOV64_IMM(BPF_REG_3, sizeof(struct test_val)),
+ BPF_MOV64_IMM(BPF_REG_4, 256),
+ BPF_EMIT_CALL(BPF_FUNC_get_stack),
+ BPF_MOV64_IMM(BPF_REG_1, 0),
+ BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_8, 32),
+ BPF_ALU64_IMM(BPF_ARSH, BPF_REG_8, 32),
+ BPF_JMP_REG(BPF_JSLT, BPF_REG_1, BPF_REG_8, 16),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_8),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_9),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_1, 32),
+ BPF_ALU64_IMM(BPF_ARSH, BPF_REG_1, 32),
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_2),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
+ BPF_MOV64_IMM(BPF_REG_5, sizeof(struct test_val)),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_5),
+ BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 4),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_9),
+ BPF_MOV64_IMM(BPF_REG_4, 0),
+ BPF_EMIT_CALL(BPF_FUNC_get_stack),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map2 = { 4 },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+ },
};
static int probe_filter_length(const struct bpf_insn *fp)
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 09/10] tools/bpf: add a test for bpf_get_stack with raw tracepoint prog
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
` (7 preceding siblings ...)
2018-04-23 21:27 ` [PATCH bpf-next v6 08/10] tools/bpf: add a verifier test case for bpf_get_stack helper and ARSH Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
2018-04-23 21:27 ` [PATCH bpf-next v6 10/10] tools/bpf: add a test for bpf_get_stack with " Yonghong Song
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
The test attached a raw_tracepoint program to sched/sched_switch.
It tested to get stack for user space, kernel space and user
space with build_id request. It also tested to get user
and kernel stack into the same buffer with back-to-back
bpf_get_stack helper calls.
Whenever the kernel stack is available, the user space
application will check to ensure that the kernel function
for raw_tracepoint ___bpf_prog_run is part of the stack.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
tools/testing/selftests/bpf/Makefile | 3 +-
tools/testing/selftests/bpf/test_get_stack_rawtp.c | 102 +++++++++++++++++
tools/testing/selftests/bpf/test_progs.c | 122 +++++++++++++++++++++
3 files changed, 226 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/test_get_stack_rawtp.c
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 0b72cc7..54e9e74 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -32,7 +32,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
test_l4lb_noinline.o test_xdp_noinline.o test_stacktrace_map.o \
sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \
sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
- test_btf_haskv.o test_btf_nokv.o
+ test_btf_haskv.o test_btf_nokv.o test_get_stack_rawtp.o
# Order correspond to 'make run_tests' order
TEST_PROGS := test_kmod.sh \
@@ -56,6 +56,7 @@ $(TEST_GEN_PROGS_EXTENDED): $(OUTPUT)/libbpf.a
$(OUTPUT)/test_dev_cgroup: cgroup_helpers.c
$(OUTPUT)/test_sock: cgroup_helpers.c
$(OUTPUT)/test_sock_addr: cgroup_helpers.c
+$(OUTPUT)/test_progs: trace_helpers.c
.PHONY: force
diff --git a/tools/testing/selftests/bpf/test_get_stack_rawtp.c b/tools/testing/selftests/bpf/test_get_stack_rawtp.c
new file mode 100644
index 0000000..ba1dcf9
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_get_stack_rawtp.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+/* Permit pretty deep stack traces */
+#define MAX_STACK_RAWTP 100
+struct stack_trace_t {
+ int pid;
+ int kern_stack_size;
+ int user_stack_size;
+ int user_stack_buildid_size;
+ __u64 kern_stack[MAX_STACK_RAWTP];
+ __u64 user_stack[MAX_STACK_RAWTP];
+ struct bpf_stack_build_id user_stack_buildid[MAX_STACK_RAWTP];
+};
+
+struct bpf_map_def SEC("maps") perfmap = {
+ .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(__u32),
+ .max_entries = 2,
+};
+
+struct bpf_map_def SEC("maps") stackdata_map = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = sizeof(struct stack_trace_t),
+ .max_entries = 1,
+};
+
+/* Allocate per-cpu space twice the needed. For the code below
+ * usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK);
+ * if (usize < 0)
+ * return 0;
+ * ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0);
+ *
+ * If we have value_size = MAX_STACK_RAWTP * sizeof(__u64),
+ * verifier will complain that access "raw_data + usize"
+ * with size "max_len - usize" may be out of bound.
+ * The maximum "raw_data + usize" is "raw_data + max_len"
+ * and the maximum "max_len - usize" is "max_len", verifier
+ * concludes that the maximum buffer access range is
+ * "raw_data[0...max_len * 2 - 1]" and hence reject the program.
+ *
+ * Doubling the to-be-used max buffer size can fix this verifier
+ * issue and avoid complicated C programming massaging.
+ * This is an acceptable workaround since there is one entry here.
+ */
+struct bpf_map_def SEC("maps") rawdata_map = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = MAX_STACK_RAWTP * sizeof(__u64) * 2,
+ .max_entries = 1,
+};
+
+SEC("tracepoint/sched/sched_switch")
+int bpf_prog1(void *ctx)
+{
+ int max_len, max_buildid_len, usize, ksize, total_size;
+ struct stack_trace_t *data;
+ void *raw_data;
+ __u32 key = 0;
+
+ data = bpf_map_lookup_elem(&stackdata_map, &key);
+ if (!data)
+ return 0;
+
+ max_len = MAX_STACK_RAWTP * sizeof(__u64);
+ max_buildid_len = MAX_STACK_RAWTP * sizeof(struct bpf_stack_build_id);
+ data->pid = bpf_get_current_pid_tgid();
+ data->kern_stack_size = bpf_get_stack(ctx, data->kern_stack,
+ max_len, 0);
+ data->user_stack_size = bpf_get_stack(ctx, data->user_stack, max_len,
+ BPF_F_USER_STACK);
+ data->user_stack_buildid_size = bpf_get_stack(
+ ctx, data->user_stack_buildid, max_buildid_len,
+ BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);
+ bpf_perf_event_output(ctx, &perfmap, 0, data, sizeof(*data));
+
+ /* write both kernel and user stacks to the same buffer */
+ raw_data = bpf_map_lookup_elem(&rawdata_map, &key);
+ if (!raw_data)
+ return 0;
+
+ usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK);
+ if (usize < 0)
+ return 0;
+
+ ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0);
+ if (ksize < 0)
+ return 0;
+
+ total_size = usize + ksize;
+ if (total_size > 0 && total_size <= max_len)
+ bpf_perf_event_output(ctx, &perfmap, 0, raw_data, total_size);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index eedda98..c148a55 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -38,6 +38,7 @@ typedef __u16 __sum16;
#include "bpf_util.h"
#include "bpf_endian.h"
#include "bpf_rlimit.h"
+#include "trace_helpers.h"
static int error_cnt, pass_cnt;
@@ -1204,6 +1205,126 @@ static void test_stacktrace_build_id(void)
return;
}
+#define MAX_CNT_RAWTP 10ull
+#define MAX_STACK_RAWTP 100
+struct get_stack_trace_t {
+ int pid;
+ int kern_stack_size;
+ int user_stack_size;
+ int user_stack_buildid_size;
+ __u64 kern_stack[MAX_STACK_RAWTP];
+ __u64 user_stack[MAX_STACK_RAWTP];
+ struct bpf_stack_build_id user_stack_buildid[MAX_STACK_RAWTP];
+};
+
+static void get_stack_raw_tp_action(void)
+{
+ FILE *f;
+
+ f = popen("taskset 1 dd if=/dev/zero of=/dev/null", "r");
+ (void) f;
+}
+
+static int get_stack_print_output(void *data, int size)
+{
+ bool good_kern_stack = false, good_user_stack = false;
+ const char *expected_func = "___bpf_prog_run";
+ struct get_stack_trace_t *e = data;
+ int i, num_stack;
+ static __u64 cnt;
+ struct ksym *ks;
+
+ cnt++;
+
+ if (size < sizeof(struct get_stack_trace_t)) {
+ __u64 *raw_data = data;
+
+ num_stack = size / sizeof(__u64);
+ for (i = 0; i < num_stack; i++) {
+ ks = ksym_search(raw_data[i]);
+ if (ks && (strcmp(ks->name, expected_func) == 0)) {
+ good_kern_stack = true;
+ good_user_stack = (i > 0);
+ }
+ }
+ } else {
+ if (e->kern_stack_size > 0) {
+ num_stack = e->kern_stack_size / sizeof(__u64);
+ for (i = 0; i < num_stack; i++) {
+ ks = ksym_search(e->kern_stack[i]);
+ if (ks && (strcmp(ks->name, expected_func) == 0))
+ good_kern_stack = true;
+ }
+ }
+ if (e->user_stack_size > 0 && e->user_stack_buildid_size > 0)
+ good_user_stack = true;
+ }
+ if (!good_kern_stack || !good_user_stack)
+ return PERF_EVENT_ERROR;
+
+ if (cnt == MAX_CNT_RAWTP)
+ return PERF_EVENT_DONE;
+
+ return PERF_EVENT_CONT;
+}
+
+static void test_get_stack_raw_tp(void)
+{
+ const char *file = "./test_get_stack_rawtp.o";
+ int efd, err, prog_fd, pmu_fd, perfmap_fd;
+ struct perf_event_attr attr = {};
+ __u32 key = 0, duration = 0;
+ struct bpf_object *obj;
+
+ err = bpf_prog_load(file, BPF_PROG_TYPE_RAW_TRACEPOINT, &obj, &prog_fd);
+ if (CHECK(err, "prog_load raw tp", "err %d errno %d\n", err, errno))
+ return;
+
+ efd = bpf_raw_tracepoint_open("sched_switch", prog_fd);
+ if (CHECK(efd < 0, "raw_tp_open", "err %d errno %d\n", efd, errno))
+ goto close_prog;
+
+ perfmap_fd = bpf_find_map(__func__, obj, "perfmap");
+ if (CHECK(perfmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
+ perfmap_fd, errno))
+ goto close_prog;
+
+ err = load_kallsyms();
+ if (CHECK(err < 0, "load_kallsyms", "err %d errno %d\n", err, errno))
+ goto close_prog;
+
+ attr.sample_type = PERF_SAMPLE_RAW;
+ attr.type = PERF_TYPE_SOFTWARE;
+ attr.config = PERF_COUNT_SW_BPF_OUTPUT;
+ pmu_fd = syscall(__NR_perf_event_open, &attr, -1/*pid*/, 0/*cpu*/,
+ -1/*group_fd*/, 0);
+ if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
+ errno))
+ goto close_prog;
+
+ err = bpf_map_update_elem(perfmap_fd, &key, &pmu_fd, BPF_ANY);
+ if (CHECK(err < 0, "bpf_map_update_elem", "err %d errno %d\n", err,
+ errno))
+ goto close_prog;
+
+ err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
+ if (CHECK(err < 0, "ioctl PERF_EVENT_IOC_ENABLE", "err %d errno %d\n",
+ err, errno))
+ goto close_prog;
+
+ err = perf_event_poller(pmu_fd, get_stack_raw_tp_action,
+ get_stack_print_output);
+ if (CHECK(err < 0, "perf_event_poller", "err %d errno %d\n", err,
+ errno))
+ goto close_prog;
+
+ goto close_prog_noerr;
+close_prog:
+ error_cnt++;
+close_prog_noerr:
+ bpf_object__close(obj);
+}
+
int main(void)
{
test_pkt_access();
@@ -1219,6 +1340,7 @@ int main(void)
test_stacktrace_map();
test_stacktrace_build_id();
test_stacktrace_map_raw_tp();
+ test_get_stack_raw_tp();
printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;
--
2.9.5
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH bpf-next v6 10/10] tools/bpf: add a test for bpf_get_stack with tracepoint prog
2018-04-23 21:27 [PATCH bpf-next v6 00/10] bpf: add bpf_get_stack helper Yonghong Song
` (8 preceding siblings ...)
2018-04-23 21:27 ` [PATCH bpf-next v6 09/10] tools/bpf: add a test for bpf_get_stack with raw tracepoint prog Yonghong Song
@ 2018-04-23 21:27 ` Yonghong Song
9 siblings, 0 replies; 13+ messages in thread
From: Yonghong Song @ 2018-04-23 21:27 UTC (permalink / raw)
To: ast, daniel, netdev, ecree; +Cc: kernel-team
The test_stacktrace_map and test_stacktrace_build_id are
enhanced to call bpf_get_stack in the helper to get the
stack trace as well. The stack traces from bpf_get_stack
and bpf_get_stackid are compared to ensure that for the
same stack as represented as the same hash, their ip addresses
or build id's must be the same.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
tools/testing/selftests/bpf/test_progs.c | 70 ++++++++++++++++++++--
.../selftests/bpf/test_stacktrace_build_id.c | 20 ++++++-
tools/testing/selftests/bpf/test_stacktrace_map.c | 19 +++++-
3 files changed, 98 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index c148a55..664db67 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -897,11 +897,47 @@ static int compare_map_keys(int map1_fd, int map2_fd)
return 0;
}
+static int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len)
+{
+ __u32 key, next_key, *cur_key_p, *next_key_p;
+ char *val_buf1, *val_buf2;
+ int i, err = 0;
+
+ val_buf1 = malloc(stack_trace_len);
+ val_buf2 = malloc(stack_trace_len);
+ cur_key_p = NULL;
+ next_key_p = &key;
+ while (bpf_map_get_next_key(smap_fd, cur_key_p, next_key_p) == 0) {
+ err = bpf_map_lookup_elem(smap_fd, next_key_p, val_buf1);
+ if (err)
+ goto out;
+ err = bpf_map_lookup_elem(amap_fd, next_key_p, val_buf2);
+ if (err)
+ goto out;
+ for (i = 0; i < stack_trace_len; i++) {
+ if (val_buf1[i] != val_buf2[i]) {
+ err = -1;
+ goto out;
+ }
+ }
+ key = *next_key_p;
+ cur_key_p = &key;
+ next_key_p = &next_key;
+ }
+ if (errno != ENOENT)
+ err = -1;
+
+out:
+ free(val_buf1);
+ free(val_buf2);
+ return err;
+}
+
static void test_stacktrace_map()
{
- int control_map_fd, stackid_hmap_fd, stackmap_fd;
+ int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
const char *file = "./test_stacktrace_map.o";
- int bytes, efd, err, pmu_fd, prog_fd;
+ int bytes, efd, err, pmu_fd, prog_fd, stack_trace_len;
struct perf_event_attr attr = {};
__u32 key, val, duration = 0;
struct bpf_object *obj;
@@ -957,6 +993,10 @@ static void test_stacktrace_map()
if (stackmap_fd < 0)
goto disable_pmu;
+ stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap");
+ if (stack_amap_fd < 0)
+ goto disable_pmu;
+
/* give some time for bpf program run */
sleep(1);
@@ -978,6 +1018,12 @@ static void test_stacktrace_map()
"err %d errno %d\n", err, errno))
goto disable_pmu_noerr;
+ stack_trace_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);
+ err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);
+ if (CHECK(err, "compare_stack_ips stackmap vs. stack_amap",
+ "err %d errno %d\n", err, errno))
+ goto disable_pmu_noerr;
+
goto disable_pmu_noerr;
disable_pmu:
error_cnt++;
@@ -1071,9 +1117,9 @@ static int extract_build_id(char *build_id, size_t size)
static void test_stacktrace_build_id(void)
{
- int control_map_fd, stackid_hmap_fd, stackmap_fd;
+ int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
const char *file = "./test_stacktrace_build_id.o";
- int bytes, efd, err, pmu_fd, prog_fd;
+ int bytes, efd, err, pmu_fd, prog_fd, stack_trace_len;
struct perf_event_attr attr = {};
__u32 key, previous_key, val, duration = 0;
struct bpf_object *obj;
@@ -1138,6 +1184,11 @@ static void test_stacktrace_build_id(void)
err, errno))
goto disable_pmu;
+ stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap");
+ if (CHECK(stack_amap_fd < 0, "bpf_find_map stack_amap",
+ "err %d errno %d\n", err, errno))
+ goto disable_pmu;
+
assert(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")
== 0);
assert(system("./urandom_read if=/dev/urandom of=/dev/zero count=4 2> /dev/null") == 0);
@@ -1189,8 +1240,15 @@ static void test_stacktrace_build_id(void)
previous_key = key;
} while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0);
- CHECK(build_id_matches < 1, "build id match",
- "Didn't find expected build ID from the map");
+ if (CHECK(build_id_matches < 1, "build id match",
+ "Didn't find expected build ID from the map"))
+ goto disable_pmu;
+
+ stack_trace_len = PERF_MAX_STACK_DEPTH
+ * sizeof(struct bpf_stack_build_id);
+ err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);
+ CHECK(err, "compare_stack_ips stackmap vs. stack_amap",
+ "err %d errno %d\n", err, errno);
disable_pmu:
ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
diff --git a/tools/testing/selftests/bpf/test_stacktrace_build_id.c b/tools/testing/selftests/bpf/test_stacktrace_build_id.c
index b755bd7..d86c281 100644
--- a/tools/testing/selftests/bpf/test_stacktrace_build_id.c
+++ b/tools/testing/selftests/bpf/test_stacktrace_build_id.c
@@ -19,7 +19,7 @@ struct bpf_map_def SEC("maps") stackid_hmap = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(__u32),
.value_size = sizeof(__u32),
- .max_entries = 10000,
+ .max_entries = 16384,
};
struct bpf_map_def SEC("maps") stackmap = {
@@ -31,6 +31,14 @@ struct bpf_map_def SEC("maps") stackmap = {
.map_flags = BPF_F_STACK_BUILD_ID,
};
+struct bpf_map_def SEC("maps") stack_amap = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = sizeof(struct bpf_stack_build_id)
+ * PERF_MAX_STACK_DEPTH,
+ .max_entries = 128,
+};
+
/* taken from /sys/kernel/debug/tracing/events/random/urandom_read/format */
struct random_urandom_args {
unsigned long long pad;
@@ -42,7 +50,10 @@ struct random_urandom_args {
SEC("tracepoint/random/urandom_read")
int oncpu(struct random_urandom_args *args)
{
+ __u32 max_len = sizeof(struct bpf_stack_build_id)
+ * PERF_MAX_STACK_DEPTH;
__u32 key = 0, val = 0, *value_p;
+ void *stack_p;
value_p = bpf_map_lookup_elem(&control_map, &key);
if (value_p && *value_p)
@@ -50,8 +61,13 @@ int oncpu(struct random_urandom_args *args)
/* The size of stackmap and stackid_hmap should be the same */
key = bpf_get_stackid(args, &stackmap, BPF_F_USER_STACK);
- if ((int)key >= 0)
+ if ((int)key >= 0) {
bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
+ stack_p = bpf_map_lookup_elem(&stack_amap, &key);
+ if (stack_p)
+ bpf_get_stack(args, stack_p, max_len,
+ BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);
+ }
return 0;
}
diff --git a/tools/testing/selftests/bpf/test_stacktrace_map.c b/tools/testing/selftests/bpf/test_stacktrace_map.c
index 76d85c5d..af111af 100644
--- a/tools/testing/selftests/bpf/test_stacktrace_map.c
+++ b/tools/testing/selftests/bpf/test_stacktrace_map.c
@@ -19,14 +19,21 @@ struct bpf_map_def SEC("maps") stackid_hmap = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(__u32),
.value_size = sizeof(__u32),
- .max_entries = 10000,
+ .max_entries = 16384,
};
struct bpf_map_def SEC("maps") stackmap = {
.type = BPF_MAP_TYPE_STACK_TRACE,
.key_size = sizeof(__u32),
.value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH,
- .max_entries = 10000,
+ .max_entries = 16384,
+};
+
+struct bpf_map_def SEC("maps") stack_amap = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH,
+ .max_entries = 16384,
};
/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
@@ -44,7 +51,9 @@ struct sched_switch_args {
SEC("tracepoint/sched/sched_switch")
int oncpu(struct sched_switch_args *ctx)
{
+ __u32 max_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);
__u32 key = 0, val = 0, *value_p;
+ void *stack_p;
value_p = bpf_map_lookup_elem(&control_map, &key);
if (value_p && *value_p)
@@ -52,8 +61,12 @@ int oncpu(struct sched_switch_args *ctx)
/* The size of stackmap and stackid_hmap should be the same */
key = bpf_get_stackid(ctx, &stackmap, 0);
- if ((int)key >= 0)
+ if ((int)key >= 0) {
bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
+ stack_p = bpf_map_lookup_elem(&stack_amap, &key);
+ if (stack_p)
+ bpf_get_stack(ctx, stack_p, max_len, 0);
+ }
return 0;
}
--
2.9.5
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