lkml.org 
[lkml]   [2013]   [Oct]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[PATCH 3.2 133/149] perf: Fix perf_cgroup_switch for sw-events
3.2.52-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Zijlstra <a.p.zijlstra@chello.nl>

commit 95cf59ea72331d0093010543b8951bb43f262cac upstream.

Jiri reported that he could trigger the WARN_ON_ONCE() in
perf_cgroup_switch() using sw-events. This is because sw-events share
a cpuctx with multiple PMUs.

Use the ->unique_pmu pointer to limit the pmu iteration to unique
cpuctx instances.

Reported-and-Tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-so7wi2zf3jjzrwcutm2mkz0j@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
kernel/events/core.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -360,6 +360,8 @@ void perf_cgroup_switch(struct task_stru

list_for_each_entry_rcu(pmu, &pmus, entry) {
cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
+ if (cpuctx->unique_pmu != pmu)
+ continue; /* ensure we process each cpuctx once */

/*
* perf_cgroup_events says at least one
@@ -383,9 +385,10 @@ void perf_cgroup_switch(struct task_stru

if (mode & PERF_CGROUP_SWIN) {
WARN_ON_ONCE(cpuctx->cgrp);
- /* set cgrp before ctxsw in to
- * allow event_filter_match() to not
- * have to pass task around
+ /*
+ * set cgrp before ctxsw in to allow
+ * event_filter_match() to not have to pass
+ * task around
*/
cpuctx->cgrp = perf_cgroup_from_task(task);
cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);


\
 
 \ /
  Last update: 2013-10-21 11:21    [W:0.455 / U:1.084 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site