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%3Ba=su...

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@vger.kernel.org know about it.

From foo@baz Wed Dec 6 18:04:41 CET 2017

From: Peter Zijlstra peterz@infradead.org Date: Tue, 5 Sep 2017 13:38:24 +0200 Subject: perf/core: Fix __perf_read_group_add() locking

From: Peter Zijlstra peterz@infradead.org

[ 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@infradead.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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@infradead.org 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