Messages in this thread Patch in this message | | | From | Darren Hart <> | Subject | [PATCH 2/4] rtmutex: add BUG_ON if a task attempts to block on two locks | Date | Fri, 9 Jul 2010 15:32:58 -0700 |
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rtmutex proxy locking complicates the logic a bit and opens up the possibility for a task to wake and attempt to take another sleeping lock without knowing it has been enqueued on another lock already. Add a BUG_ON to catch this scenario early.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: John Kacur <jkacur@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mike Galbraith <efault@gmx.de> --- kernel/rtmutex.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index baac7d9..22f9d18 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -459,6 +459,9 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, top_waiter = rt_mutex_top_waiter(lock); plist_add(&waiter->list_entry, &lock->wait_list); + /* Tasks can only block on one lock at a time. */ + BUG_ON(task->pi_blocked_on != NULL); + task->pi_blocked_on = waiter; raw_spin_unlock(&task->pi_lock); -- 1.7.0.4
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