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- Revert a commit to spinlock cleanup guards that got caught up

Browse Source 
in the subtle limitations & fragility of guards (again...) and
    caused a regression (Peter Zijlstra)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-urgent-2026-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fix from Ingo Molnar:

 - Revert a commit to spinlock cleanup guards that got caught up
   in the subtle limitations & fragility of guards (again...) and
   caused a regression (Peter Zijlstra)

* tag 'locking-urgent-2026-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking: Revert switching guards to _irq_{disable,enable}()
This commit is contained in:
Linus Torvalds 2026-08-30 09:57:35 -07:00
commit 637836563d
2 changed files with 20 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
include/linux/spinlock.h
View File

@ -572,12 +572,12 @@ DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_nested, __acquires(_T), __releases(*(raw
#define class_raw_spinlock_nested_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(raw_spinlock_nested, _T)
DEFINE_LOCK_GUARD_1(raw_spinlock_irq, raw_spinlock_t,
raw_spin_lock_irq_disable(_T->lock),
raw_spin_unlock_irq_enable(_T->lock))
raw_spin_lock_irq(_T->lock),
raw_spin_unlock_irq(_T->lock))
DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irq, __acquires(_T), __releases(*(raw_spinlock_t **)_T))
#define class_raw_spinlock_irq_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(raw_spinlock_irq, _T)
DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irq, _try, raw_spin_trylock_irq_disable(_T->lock))
DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irq, _try, raw_spin_trylock_irq(_T->lock))
DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irq_try, __acquires(_T), __releases(*(raw_spinlock_t **)_T))
#define class_raw_spinlock_irq_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(raw_spinlock_irq_try, _T)
@ -592,13 +592,14 @@ DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_bh_try, __acquires(_T), __releases(*(raw
#define class_raw_spinlock_bh_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(raw_spinlock_bh_try, _T)
DEFINE_LOCK_GUARD_1(raw_spinlock_irqsave, raw_spinlock_t,
raw_spin_lock_irq_disable(_T->lock),
raw_spin_unlock_irq_enable(_T->lock))
raw_spin_lock_irqsave(_T->lock, _T->flags),
raw_spin_unlock_irqrestore(_T->lock, _T->flags),
unsigned long flags)
DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irqsave, __acquires(_T), __releases(*(raw_spinlock_t **)_T))
#define class_raw_spinlock_irqsave_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(raw_spinlock_irqsave, _T)
DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irqsave, _try,
raw_spin_trylock_irq_disable(_T->lock))
raw_spin_trylock_irqsave(_T->lock, _T->flags))
DECLARE_LOCK_GUARD_1_ATTRS(raw_spinlock_irqsave_try, __acquires(_T), __releases(*(raw_spinlock_t **)_T))
#define class_raw_spinlock_irqsave_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(raw_spinlock_irqsave_try, _T)
@ -617,13 +618,13 @@ DECLARE_LOCK_GUARD_1_ATTRS(spinlock_try, __acquires(_T), __releases(*(spinlock_t
#define class_spinlock_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinlock_try, _T)
DEFINE_LOCK_GUARD_1(spinlock_irq, spinlock_t,
spin_lock_irq_disable(_T->lock),
spin_unlock_irq_enable(_T->lock))
spin_lock_irq(_T->lock),
spin_unlock_irq(_T->lock))
DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irq, __acquires(_T), __releases(*(spinlock_t **)_T))
#define class_spinlock_irq_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinlock_irq, _T)
DEFINE_LOCK_GUARD_1_COND(spinlock_irq, _try,
spin_trylock_irq_disable(_T->lock))
spin_trylock_irq(_T->lock))
DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irq_try, __acquires(_T), __releases(*(spinlock_t **)_T))
#define class_spinlock_irq_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinlock_irq_try, _T)
@ -639,13 +640,14 @@ DECLARE_LOCK_GUARD_1_ATTRS(spinlock_bh_try, __acquires(_T), __releases(*(spinloc
#define class_spinlock_bh_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinlock_bh_try, _T)
DEFINE_LOCK_GUARD_1(spinlock_irqsave, spinlock_t,
spin_lock_irq_disable(_T->lock),
spin_unlock_irq_enable(_T->lock))
spin_lock_irqsave(_T->lock, _T->flags),
spin_unlock_irqrestore(_T->lock, _T->flags),
unsigned long flags)
DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irqsave, __acquires(_T), __releases(*(spinlock_t **)_T))
#define class_spinlock_irqsave_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinlock_irqsave, _T)
DEFINE_LOCK_GUARD_1_COND(spinlock_irqsave, _try,
spin_trylock_irq_disable(_T->lock))
spin_trylock_irqsave(_T->lock, _T->flags))
DECLARE_LOCK_GUARD_1_ATTRS(spinlock_irqsave_try, __acquires(_T), __releases(*(spinlock_t **)_T))
#define class_spinlock_irqsave_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(spinlock_irqsave_try, _T)

12
kernel/sched/fair.c
View File

@ -7253,7 +7253,7 @@ static bool distribute_cfs_runtime(struct cfs_bandwidth *cfs_b)
* period the timer is deactivated until scheduling resumes; cfs_b->idle is
* used to track this state.
*/
static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags)
__must_hold(&cfs_b->lock)
{
int throttled;
@ -7288,10 +7288,10 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
* This check is repeated as we release cfs_b->lock while we unthrottle.
*/
while (throttled && cfs_b->runtime > 0) {
raw_spin_unlock_irq_enable(&cfs_b->lock);
raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
/* we can't nest cfs_b->lock while distributing bandwidth */
throttled = distribute_cfs_runtime(cfs_b);
raw_spin_lock_irq_disable(&cfs_b->lock);
raw_spin_lock_irqsave(&cfs_b->lock, flags);
}
/*
@ -7399,7 +7399,7 @@ static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
{
/* confirm we're still not at a refresh boundary */
scoped_guard(raw_spinlock_irq, &cfs_b->lock) {
scoped_guard(raw_spinlock_irqsave, &cfs_b->lock) {
u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
cfs_b->slack_started = false;
@ -7484,14 +7484,14 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
int idle = 0;
int count = 0;
guard(raw_spinlock_irq)(&cfs_b->lock);
CLASS(raw_spinlock_irqsave, cfsb_guard)(&cfs_b->lock);
for (;;) {
overrun = hrtimer_forward_now(timer, cfs_b->period);
if (!overrun)
break;
idle = do_sched_cfs_period_timer(cfs_b, overrun);
idle = do_sched_cfs_period_timer(cfs_b, overrun, cfsb_guard.flags);
if (++count > 3) {
u64 new, old = ktime_to_ns(cfs_b->period);