[PATCH bpf] selftests/bpf: fix stacktrace_build_id with missing kprobe/urandom_read

[PATCH bpf] selftests/bpf: fix stacktrace_build_id with missing kprobe/urandom_read

[Song Liu]

Kernel function urandom_read is replaced with urandom_read_iter.
Therefore, kprobe on urandom_read is not working any more:

[root@eth50-1 bpf]# ./test_progs -n 161
test_stacktrace_build_id:PASS:skel_open_and_load 0 nsec
libbpf: kprobe perf_event_open() failed: No such file or directory
libbpf: prog 'oncpu': failed to create kprobe 'urandom_read+0x0' \
        perf event: No such file or directory
libbpf: prog 'oncpu': failed to auto-attach: -2
test_stacktrace_build_id:FAIL:attach_tp err -2
161     stacktrace_build_id:FAIL

Fix this by replacing urandom_read with urandom_read_iter in the test.

Fixes: 1b388e7765f2 ("random: convert to using fops->read_iter()")
Reported-by: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Song Liu <song@kernel.org>
---
 tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c b/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
index 6c62bfb8bb6f..0c4426592a26 100644
--- a/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
+++ b/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
@@ -39,7 +39,7 @@ struct {
 	__type(value, stack_trace_t);
 } stack_amap SEC(".maps");
 
-SEC("kprobe/urandom_read")
+SEC("kprobe/urandom_read_iter")
 int oncpu(struct pt_regs *args)
 {
 	__u32 max_len = sizeof(struct bpf_stack_build_id)
-- 
2.30.2

Re: [PATCH bpf] selftests/bpf: fix stacktrace_build_id with missing kprobe/urandom_read

[David Vernet]

On Thu, May 26, 2022 at 12:16:08PM -0700, Song Liu wrote:
> Kernel function urandom_read is replaced with urandom_read_iter.
> Therefore, kprobe on urandom_read is not working any more:
> 
> [root@eth50-1 bpf]# ./test_progs -n 161
> test_stacktrace_build_id:PASS:skel_open_and_load 0 nsec
> libbpf: kprobe perf_event_open() failed: No such file or directory
> libbpf: prog 'oncpu': failed to create kprobe 'urandom_read+0x0' \
>         perf event: No such file or directory
> libbpf: prog 'oncpu': failed to auto-attach: -2
> test_stacktrace_build_id:FAIL:attach_tp err -2
> 161     stacktrace_build_id:FAIL
> 
> Fix this by replacing urandom_read with urandom_read_iter in the test.
> 
> Fixes: 1b388e7765f2 ("random: convert to using fops->read_iter()")
> Reported-by: Mykola Lysenko <mykolal@fb.com>
> Signed-off-by: Song Liu <song@kernel.org>
> ---
>  tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c b/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
> index 6c62bfb8bb6f..0c4426592a26 100644
> --- a/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
> +++ b/tools/testing/selftests/bpf/progs/test_stacktrace_build_id.c
> @@ -39,7 +39,7 @@ struct {
>  	__type(value, stack_trace_t);
>  } stack_amap SEC(".maps");
>  
> -SEC("kprobe/urandom_read")
> +SEC("kprobe/urandom_read_iter")
>  int oncpu(struct pt_regs *args)
>  {
>  	__u32 max_len = sizeof(struct bpf_stack_build_id)
> -- 
> 2.30.2
> 

Acked-by: David Vernet <void@manifault.com>

Re: [PATCH bpf] selftests/bpf: fix stacktrace_build_id with missing kprobe/urandom_read

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Thu, 26 May 2022 12:16:08 -0700 you wrote:
> Kernel function urandom_read is replaced with urandom_read_iter.
> Therefore, kprobe on urandom_read is not working any more:
> 
> [root@eth50-1 bpf]# ./test_progs -n 161
> test_stacktrace_build_id:PASS:skel_open_and_load 0 nsec
> libbpf: kprobe perf_event_open() failed: No such file or directory
> libbpf: prog 'oncpu': failed to create kprobe 'urandom_read+0x0' \
>         perf event: No such file or directory
> libbpf: prog 'oncpu': failed to auto-attach: -2
> test_stacktrace_build_id:FAIL:attach_tp err -2
> 161     stacktrace_build_id:FAIL
> 
> [...]

Here is the summary with links:
  - [bpf] selftests/bpf: fix stacktrace_build_id with missing kprobe/urandom_read
    https://git.kernel.org/bpf/bpf/c/59ed76fe2f98

You are awesome, thank you!
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