[GIT pull] locking/urgent for v6.11-rc7
From: Thomas Gleixner
Date: Sun Sep 01 2024 - 07:44:19 EST
Linus,
please pull the latest locking/urgent branch from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-2024-08-25
up to: d33d26036a02: rtmutex: Drop rt_mutex::wait_lock before scheduling
A single fix for rt_mutex:
The deadlock detection code drops into an infinite scheduling loop while
still holding rt_mutex::wait_lock, which rightfully triggers a
'scheduling in atomic' warning. Unlock it before that.
Thanks,
tglx
------------------>
Roland Xu (1):
rtmutex: Drop rt_mutex::wait_lock before scheduling
kernel/locking/rtmutex.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 88d08eeb8bc0..fba1229f1de6 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1644,6 +1644,7 @@ static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock,
}
static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock,
+ struct rt_mutex_base *lock,
struct rt_mutex_waiter *w)
{
/*
@@ -1656,10 +1657,10 @@ static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock,
if (build_ww_mutex() && w->ww_ctx)
return;
- /*
- * Yell loudly and stop the task right here.
- */
+ raw_spin_unlock_irq(&lock->wait_lock);
+
WARN(1, "rtmutex deadlock detected\n");
+
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
rt_mutex_schedule();
@@ -1713,7 +1714,7 @@ static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock,
} else {
__set_current_state(TASK_RUNNING);
remove_waiter(lock, waiter);
- rt_mutex_handle_deadlock(ret, chwalk, waiter);
+ rt_mutex_handle_deadlock(ret, chwalk, lock, waiter);
}
/*