Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'locking-urgent-2024-12-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Ingo Molnar:
"Fix missed rtmutex wakeups causing sporadic boot hangs and other
misbehavior"
* tag 'locking-urgent-2024-12-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Make sure we wake anything on the wake_q when we release the lock->wait_lock
+17
-3
+16
-2
kernel/locking/rtmutex.c
+16
-2
kernel/locking/rtmutex.c
···
1292
1292
*/
1293
1293
get_task_struct(owner);
1294
1294
1295
+
preempt_disable();
1295
1296
raw_spin_unlock_irq(&lock->wait_lock);
1297
+
/* wake up any tasks on the wake_q before calling rt_mutex_adjust_prio_chain */
1298
+
wake_up_q(wake_q);
1299
+
wake_q_init(wake_q);
1300
+
preempt_enable();
1301
+
1296
1302
1297
1303
res = rt_mutex_adjust_prio_chain(owner, chwalk, lock,
1298
1304
next_lock, waiter, task);
···
1602
1596
* or TASK_UNINTERRUPTIBLE)
1603
1597
* @timeout: the pre-initialized and started timer, or NULL for none
1604
1598
* @waiter: the pre-initialized rt_mutex_waiter
1599
+
* @wake_q: wake_q of tasks to wake when we drop the lock->wait_lock
1605
1600
*
1606
1601
* Must be called with lock->wait_lock held and interrupts disabled
1607
1602
*/
···
1610
1603
struct ww_acquire_ctx *ww_ctx,
1611
1604
unsigned int state,
1612
1605
struct hrtimer_sleeper *timeout,
1613
-
struct rt_mutex_waiter *waiter)
1606
+
struct rt_mutex_waiter *waiter,
1607
+
struct wake_q_head *wake_q)
1614
1608
__releases(&lock->wait_lock) __acquires(&lock->wait_lock)
1615
1609
{
1616
1610
struct rt_mutex *rtm = container_of(lock, struct rt_mutex, rtmutex);
···
1642
1634
owner = rt_mutex_owner(lock);
1643
1635
else
1644
1636
owner = NULL;
1637
+
preempt_disable();
1645
1638
raw_spin_unlock_irq(&lock->wait_lock);
1639
+
if (wake_q) {
1640
+
wake_up_q(wake_q);
1641
+
wake_q_init(wake_q);
1642
+
}
1643
+
preempt_enable();
1646
1644
1647
1645
if (!owner || !rtmutex_spin_on_owner(lock, waiter, owner))
1648
1646
rt_mutex_schedule();
···
1722
1708
1723
1709
ret = task_blocks_on_rt_mutex(lock, waiter, current, ww_ctx, chwalk, wake_q);
1724
1710
if (likely(!ret))
1725
-
ret = rt_mutex_slowlock_block(lock, ww_ctx, state, NULL, waiter);
1711
+
ret = rt_mutex_slowlock_block(lock, ww_ctx, state, NULL, waiter, wake_q);
1726
1712
1727
1713
if (likely(!ret)) {
1728
1714
/* acquired the lock */
+1
-1
kernel/locking/rtmutex_api.c
+1
-1
kernel/locking/rtmutex_api.c
···
383
383
raw_spin_lock_irq(&lock->wait_lock);
384
384
/* sleep on the mutex */
385
385
set_current_state(TASK_INTERRUPTIBLE);
386
-
ret = rt_mutex_slowlock_block(lock, NULL, TASK_INTERRUPTIBLE, to, waiter);
386
+
ret = rt_mutex_slowlock_block(lock, NULL, TASK_INTERRUPTIBLE, to, waiter, NULL);
387
387
/*
388
388
* try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
389
389
* have to fix that up.