This is a note to let you know that I've just added the patch titled
perf/core: Fix __perf_read_group_add() locking
to the 4.14-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-core-fix-__perf_read_group_add-locking.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Dec 6 18:04:41 CET 2017
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Tue, 5 Sep 2017 13:38:24 +0200
Subject: perf/core: Fix __perf_read_group_add() locking
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
[ Upstream commit a9cd8194e1e6bd09619954721dfaf0f94fe2003e ]
Event timestamps are serialized using ctx->lock, make sure to hold it
over reading all values.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4433,6 +4433,8 @@ static int __perf_read_group_add(struct
if (ret)
return ret;
+ raw_spin_lock_irqsave(&ctx->lock, flags);
+
/*
* Since we co-schedule groups, {enabled,running} times of siblings
* will be identical to those of the leader, so we only publish one
@@ -4455,8 +4457,6 @@ static int __perf_read_group_add(struct
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
- raw_spin_lock_irqsave(&ctx->lock, flags);
-
list_for_each_entry(sub, &leader->sibling_list, group_entry) {
values[n++] += perf_event_count(sub);
if (read_format & PERF_FORMAT_ID)
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-4.14/perf-tools-fix-leaking-rec_argv-in-error-cases.patch
queue-4.14/locking-refcounts-x86-asm-use-unique-.text-section-for-refcount-exceptions.patch
queue-4.14/selftests-x86-ldt_get-add-a-few-additional-tests-for-limits.patch
queue-4.14/mm-x86-mm-fix-performance-regression-in-get_user_pages_fast.patch
queue-4.14/selftests-x86-ldt_gdt-robustify-against-set_thread_area-and-lar-oddities.patch
queue-4.14/kprobes-use-synchronize_rcu_tasks-for-optprobe-with-config_preempt-y.patch
queue-4.14/x86-entry-use-syscall_define-macros-for-sys_modify_ldt.patch
queue-4.14/kprobes-x86-disable-preemption-in-ftrace-based-jprobes.patch
queue-4.14/locking-refcounts-x86-asm-enable-config_arch_has_refcount.patch
queue-4.14/perf-core-fix-__perf_read_group_add-locking.patch