Commit 83f44ae0 authored Jun 26, 2019 by Song Liu Committed by Thomas Gleixner Jun 28, 2019

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:

  d15d3568 ("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: d15d3568 ("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

parent c1f7fec1

arch/x86/events/core.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -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_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);

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