3.12.54-rt73-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Yimin debugged that in case of a PI wakeup in progress when rt_mutex_start_proxy_lock() calls task_blocks_on_rt_mutex() the latter returns -EAGAIN and in consequence the remove_waiter() call runs into a BUG_ON() because there is nothing to remove. Guard it with rt_mutex_has_waiters(). This is a quick fix which is easy to backport. The proper fix is to have a central check in remove_waiter() so we can call it unconditionally. Reported-and-debugged-by: Yimin Deng <yimin11.deng@xxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: stable-rt@xxxxxxxxxxxxxxx Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> --- kernel/rtmutex.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 7601c1332a88..03439f1bc5ea 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -2065,7 +2065,7 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock, ret = 0; } - if (unlikely(ret)) + if (ret && rt_mutex_has_waiters(lock)) remove_waiter(lock, waiter); raw_spin_unlock(&lock->wait_lock); -- 2.7.0 -- To unsubscribe from this list: send the line "unsubscribe stable-rt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
