| Message ID | 20190521204813.1167784-1-songliubraving@fb.com |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | perf/x86: always include regs->ip in callchain | expand |
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 >
> 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 >>
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);
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(-)