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authorBrad Mouring <bmouring@ni.com>2015-01-14 15:11:38 -0600
committerAnders Roxell <anders.roxell@linaro.org>2015-06-01 12:03:34 +0200
commit46c709a5a34046f45388f4ae01a33ef8e7b168ab (patch)
treebc6da2bc8ffd1e99c7b4dfa7c75f25f588648ccb
parente8bbf869116e8a4fa6dfccc1216ff5d55e6ef844 (diff)
rtmutex.c: Fix incorrect waiter check
In task_blocks_on_lock, there's a null check on pi_blocked_on of the task_struct. This pointer can encode the fact that the task that contains the pointer is waking (preventing requeuing) and therefore is non-null. Use the inline function to avoid dereferencing an invalid "pointer" Signed-off-by: Brad Mouring <brad.mouring@ni.com> Reported-by: Ben Shelton <ben.shelton@ni.com> Reviewed-by: T Makphaibulchoke <tmac@hp.com> Tested-by: T Makphaibulchoke <tmac@hp.com> Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--kernel/locking/rtmutex.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index ec72272ab73a..74a824523d3a 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -361,7 +361,8 @@ int max_lock_depth = 1024;
static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
{
- return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
+ return rt_mutex_real_waiter(p->pi_blocked_on) ?
+ p->pi_blocked_on->lock : NULL;
}
/*