This is a note to let you know that I've just added the patch titled
futex: Add missing error handling to FUTEX_REQUEUE_PI
to the 4.9-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:
futex-add-missing-error-handling-to-futex_requeue_pi.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9bbb25afeb182502ca4f2c4f3f88af0681b34cae Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Sat, 4 Mar 2017 10:27:19 +0100
Subject: futex: Add missing error handling to FUTEX_REQUEUE_PI
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit 9bbb25afeb182502ca4f2c4f3f88af0681b34cae upstream.
Thomas spotted that fixup_pi_state_owner() can return errors and we
fail to unlock the rt_mutex in that case.
Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
Cc: juri.lelli@xxxxxxx
Cc: bigeasy@xxxxxxxxxxxxx
Cc: xlpang@xxxxxxxxxx
Cc: rostedt@xxxxxxxxxxx
Cc: mathieu.desnoyers@xxxxxxxxxxxx
Cc: jdesfossez@xxxxxxxxxxxx
Cc: dvhart@xxxxxxxxxxxxx
Cc: bristot@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20170304093558.867401760@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/futex.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2896,6 +2896,8 @@ static int futex_wait_requeue_pi(u32 __u
if (q.pi_state && (q.pi_state->owner != current)) {
spin_lock(q.lock_ptr);
ret = fixup_pi_state_owner(uaddr2, &q, current);
+ if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current)
+ rt_mutex_unlock(&q.pi_state->pi_mutex);
/*
* Drop the reference to the pi state which
* the requeue_pi() code acquired for us.
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-4.9/futex-fix-potential-use-after-free-in-futex_requeue_pi.patch
queue-4.9/futex-add-missing-error-handling-to-futex_requeue_pi.patch
queue-4.9/x86-perf-fix-cr4.pce-propagation-to-use-active_mm-instead-of-mm.patch
queue-4.9/locking-rwsem-fix-down_write_killable-for-config_rwsem_generic_spinlock-y.patch
queue-4.9/x86-tsc-fix-art-for-tsc_known_freq.patch