From c9ac083943df72c68956c50116982516ff3e2077 Mon Sep 17 00:00:00 2001 From: Brad Mouring Date: Wed, 14 Jan 2015 15:11:38 -0600 Subject: [PATCH] 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 Reported-by: Ben Shelton Reviewed-by: T Makphaibulchoke Tested-by: T Makphaibulchoke Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt --- kernel/locking/rtmutex.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) 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; } /*