[tip:core/urgent] futex: Test for pi_mutex on fault in futex_wait_requeue_pi()

From: tip-bot for Darren Hart
Date: Tue Jul 24 2012 - 10:22:55 EST


Commit-ID: b6070a8d9853eda010a549fa9a09eb8d7269b929
Gitweb: http://git.kernel.org/tip/b6070a8d9853eda010a549fa9a09eb8d7269b929
Author: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 20 Jul 2012 11:53:29 -0700
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 24 Jul 2012 16:02:56 +0200

futex: Test for pi_mutex on fault in futex_wait_requeue_pi()

If fixup_pi_state_owner() faults, pi_mutex may be NULL. Test
for pi_mutex != NULL before testing the owner against current
and possibly unlocking it.

Signed-off-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/dc59890338fc413606f04e5c5b131530734dae3d.1342809673.git.dvhart@xxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/futex.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index e2b0fb9..05018bf 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2370,7 +2370,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
* fault, unlock the rt_mutex and return the fault to userspace.
*/
if (ret == -EFAULT) {
- if (rt_mutex_owner(pi_mutex) == current)
+ if (pi_mutex && rt_mutex_owner(pi_mutex) == current)
rt_mutex_unlock(pi_mutex);
} else if (ret == -EINTR) {
/*
--
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