* [PATCH] perf/x86: always include regs->ip in callchain
@ 2019-05-21 20:48 Song Liu
2019-05-22 13:58 ` Peter Zijlstra
0 siblings, 1 reply; 3+ messages in thread
From: Song Liu @ 2019-05-21 20:48 UTC (permalink / raw)
To: linux-kernel, bpf; +Cc: kernel-team, Song Liu, Kairui Song, Peter Zijlstra
Commit d15d356887e7 removes regs->ip for !perf_hw_regs(regs) case. This
breaks tests like test_stacktrace_map from selftests/bpf/tests_prog.
This patch adds regs->ip back.
Fixes: d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
Cc: Kairui Song <kasong@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
---
arch/x86/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index f315425d8468..7b8a9eb4d5fd 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2402,9 +2402,9 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
return;
}
+ if (perf_callchain_store(entry, regs->ip))
+ return;
if (perf_hw_regs(regs)) {
- if (perf_callchain_store(entry, regs->ip))
- return;
unwind_start(&state, current, regs, NULL);
} else {
unwind_start(&state, current, NULL, (void *)regs->sp);
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] perf/x86: always include regs->ip in callchain
2019-05-21 20:48 [PATCH] perf/x86: always include regs->ip in callchain Song Liu
@ 2019-05-22 13:58 ` Peter Zijlstra
2019-05-22 16:12 ` Song Liu
0 siblings, 1 reply; 3+ messages in thread
From: Peter Zijlstra @ 2019-05-22 13:58 UTC (permalink / raw)
To: Song Liu; +Cc: linux-kernel, bpf, kernel-team, Kairui Song, Josh Poimboeuf
On Tue, May 21, 2019 at 01:48:13PM -0700, Song Liu wrote:
> Commit d15d356887e7 removes regs->ip for !perf_hw_regs(regs) case. This
> breaks tests like test_stacktrace_map from selftests/bpf/tests_prog.
That test is broken by something else; just the one entry is wrong too.
That said, yes the patch below is actually correct, but the above
description is misleading at best.
> This patch adds regs->ip back.
>
> Fixes: d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
> Cc: Kairui Song <kasong@redhat.com>
> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> ---
> arch/x86/events/core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index f315425d8468..7b8a9eb4d5fd 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -2402,9 +2402,9 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
> return;
> }
>
> + if (perf_callchain_store(entry, regs->ip))
> + return;
> if (perf_hw_regs(regs)) {
> - if (perf_callchain_store(entry, regs->ip))
> - return;
> unwind_start(&state, current, regs, NULL);
> } else {
> unwind_start(&state, current, NULL, (void *)regs->sp);
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] perf/x86: always include regs->ip in callchain
2019-05-22 13:58 ` Peter Zijlstra
@ 2019-05-22 16:12 ` Song Liu
0 siblings, 0 replies; 3+ messages in thread
From: Song Liu @ 2019-05-22 16:12 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-kernel, bpf, Kernel Team, Kairui Song, Josh Poimboeuf
> On May 22, 2019, at 6:58 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Tue, May 21, 2019 at 01:48:13PM -0700, Song Liu wrote:
>> Commit d15d356887e7 removes regs->ip for !perf_hw_regs(regs) case. This
>> breaks tests like test_stacktrace_map from selftests/bpf/tests_prog.
>
> That test is broken by something else; just the one entry is wrong too.
>
> That said, yes the patch below is actually correct, but the above
> description is misleading at best.
How about we change it to:
Commit d15d356887e7 removes regs->ip for !perf_hw_regs(regs) case. This
patch adds regs->ip back.
Shall I send v2 with the change?
Thanks,
Song
>
>> This patch adds regs->ip back.
>>
>> Fixes: d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
>> Cc: Kairui Song <kasong@redhat.com>
>> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>> ---
>> arch/x86/events/core.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
>> index f315425d8468..7b8a9eb4d5fd 100644
>> --- a/arch/x86/events/core.c
>> +++ b/arch/x86/events/core.c
>> @@ -2402,9 +2402,9 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
>> return;
>> }
>>
>> + if (perf_callchain_store(entry, regs->ip))
>> + return;
>> if (perf_hw_regs(regs)) {
>> - if (perf_callchain_store(entry, regs->ip))
>> - return;
>> unwind_start(&state, current, regs, NULL);
>> } else {
>> unwind_start(&state, current, NULL, (void *)regs->sp);
>> --
>> 2.17.1
>>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-05-22 16:13 UTC | newest]
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2019-05-22 13:58 ` Peter Zijlstra
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