Commit-ID: 83f44ae0f8afcc9da659799db8693f74847e66b3
Gitweb: https://git.kernel.org/tip/83f44ae0f8afcc9da659799db8693f74847e66b3
Author: Song Liu <songliubraving@xxxxxx>
AuthorDate: Wed, 26 Jun 2019 19:33:52 -0500
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Fri, 28 Jun 2019 00:11:20 +0200
perf/x86: Always store regs->ip in perf_callchain_kernel()
The stacktrace_map_raw_tp BPF selftest is failing because the RIP saved by
perf_arch_fetch_caller_regs() isn't getting saved by perf_callchain_kernel().
This was broken by the following commit:
d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
With that change, when starting with non-HW regs, the unwinder starts
with the current stack frame and unwinds until it passes up the frame
which called perf_arch_fetch_caller_regs(). So regs->ip needs to be
saved deliberately.
Fixes: d15d356887e7 ("perf/x86: Make perf callchains work without CONFIG_FRAME_POINTER")
Signed-off-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Kairui Song <kasong@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Link: https://lkml.kernel.org/r/3975a298fa52b506fea32666d8ff6a13467eee6d.1561595111.git.jpoimboe@xxxxxxxxxx
---
arch/x86/events/core.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index f315425d8468..4fb3ca1e699d 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2402,13 +2402,13 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
return;
}
- if (perf_hw_regs(regs)) {
- if (perf_callchain_store(entry, regs->ip))
- return;
+ if (perf_callchain_store(entry, regs->ip))
+ return;
+
+ if (perf_hw_regs(regs))
unwind_start(&state, current, regs, NULL);
- } else {
+ else
unwind_start(&state, current, NULL, (void *)regs->sp);
- }
for (; !unwind_done(&state); unwind_next_frame(&state)) {
addr = unwind_get_return_address(&state);
|