38 lines
1.3 KiB
Diff
38 lines
1.3 KiB
Diff
|
From eac753e84595fc2c62a2e019a05d53563cacbc07 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Thomas Gleixner <tglx@linutronix.de>
|
||
|
|
Date: Fri, 6 Nov 2015 18:51:03 +0100
|
||
|
|
Subject: [PATCH 033/365] rtmutex: Handle non enqueued waiters gracefully
|
||
|
|
|
||
|
|
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@gmail.com>
|
||
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
||
|
|
Cc: stable-rt@vger.kernel.org
|
||
|
|
---
|
||
|
|
kernel/locking/rtmutex.c | 2 +-
|
||
|
|
1 file changed, 1 insertion(+), 1 deletion(-)
|
||
|
|
|
||
|
|
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
|
||
|
|
index 1c032c286efe..b0e7b222399f 100644
|
||
|
|
--- a/kernel/locking/rtmutex.c
|
||
|
|
+++ b/kernel/locking/rtmutex.c
|
||
|
|
@@ -1697,7 +1697,7 @@ 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);
|
||
|
|
|
||
|
|
debug_rt_mutex_print_deadlock(waiter);
|
||
|
|
--
|
||
|
|
2.28.0
|
||
|
|
|