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authorSong Liu <songliubraving@fb.com>2019-06-26 19:33:52 -0500
committerThomas Gleixner <tglx@linutronix.de>2019-06-28 00:11:20 +0200
commit83f44ae0f8afcc9da659799db8693f74847e66b3 (patch)
tree97dbd7bf501484ccf72a747381e1b32c1c31e172 /arch/x86
parentc1f7fec1eb6a2c86d01bc22afce772c743451d88 (diff)
downloadlinux-83f44ae0f8afcc9da659799db8693f74847e66b3.tar.gz
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@fb.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kairui Song <kasong@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/3975a298fa52b506fea32666d8ff6a13467eee6d.1561595111.git.jpoimboe@redhat.com

Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/events/core.c10
1 files 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);