linux-kernel - [PATCH 2/6] oprofile/x86: add regs->ip to oprofile trace

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Date:   Wed, 24 Aug 2016 11:50:15 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Andy Lutomirski <luto@...capital.net>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Brian Gerst <brgerst@...il.com>,
        Kees Cook <keescook@...omium.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Frederic Weisbecker <fweisbec@...il.com>,
        Byungchul Park <byungchul.park@....com>,
        Nilay Vaish <nilayvaish@...il.com>,
        Robert Richter <rric@...nel.org>
Subject: [PATCH 2/6] oprofile/x86: add regs->ip to oprofile trace

dump_trace() doesn't add the interrupted instruction's address to the
trace, so add it manually.  This makes the profile more useful, and also
makes it more consistent with what perf profiling does.

Cc: Robert Richter <rric@...nel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 arch/x86/oprofile/backtrace.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index cb31a44..2ef6c8b 100644
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -114,9 +114,16 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
 
 	if (!user_mode(regs)) {
 		unsigned long stack = kernel_stack_pointer(regs);
-		if (depth)
-			dump_trace(NULL, regs, (unsigned long *)stack, 0,
-				   &backtrace_ops, &depth);
+
+		if (!depth)
+			return;
+
+		oprofile_add_trace(regs->ip);
+		if (!--depth)
+			return;
+
+		dump_trace(NULL, regs, (unsigned long *)stack, 0,
+			   &backtrace_ops, &depth);
 		return;
 	}
 
-- 
2.7.4