This is a note to let you know that I've just added the patch titled
perf: Do not allow optimized switch for non-cloned events
to the 3.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-do-not-allow-optimized-switch-for-non-cloned-events.patch
and it can be found in the queue-3.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1f9a7268c67f0290837aada443d28fd953ddca90 Mon Sep 17 00:00:00 2001
From: Jiri Olsa <jolsa@xxxxxxxxxx>
Date: Tue, 24 Jun 2014 10:20:25 +0200
Subject: perf: Do not allow optimized switch for non-cloned events
From: Jiri Olsa <jolsa@xxxxxxxxxx>
commit 1f9a7268c67f0290837aada443d28fd953ddca90 upstream.
The context check in perf_event_context_sched_out allows
non-cloned context to be part of the optimized schedule
out switch.
This could move non-cloned context into another workload
child. Once this child exits, the context is closed and
leaves all original (parent) events in closed state.
Any other new cloned event will have closed state and not
measure anything. And probably causing other odd bugs.
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1403598026-2310-2-git-send-email-jolsa@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/events/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2315,7 +2315,7 @@ static void perf_event_context_sched_out
next_parent = rcu_dereference(next_ctx->parent_ctx);
/* If neither context have a parent context; they cannot be clones. */
- if (!parent && !next_parent)
+ if (!parent || !next_parent)
goto unlock;
if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
Patches currently in stable-queue which might be from jolsa@xxxxxxxxxx are
queue-3.15/perf-do-not-allow-optimized-switch-for-non-cloned-events.patch
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