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locking/mutex: Make mutex::wait_lock irq safe

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With the proxy-execution series, we traverse the task->mutex->task
blocked_on/owner chain in the scheduler core. We do this while holding
the rq::lock to keep the structures in place while taking and
releasing the alternating lock types.

Since the mutex::wait_lock is one of the locks we will take in this
way under the rq::lock in the scheduler core, we need to make sure
that its usage elsewhere is irq safe.

[rebase & fix {un,}lock_wait_lock helpers in ww_mutex.h]
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Connor O'Brien <connoro@google.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Metin Kaya <metin.kaya@arm.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: Metin Kaya <metin.kaya@arm.com>
Link: https://lore.kernel.org/r/20241009235352.1614323-3-jstultz@google.com
This commit is contained in:
Juri Lelli 2024-10-09 16:53:35 -07:00 committed by Peter Zijlstra
parent 894d1b3db4
commit 5ec58525a1
2 changed files with 21 additions and 18 deletions
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18
kernel/locking/mutex.c
View File

@ -578,6 +578,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
DEFINE_WAKE_Q(wake_q);
struct mutex_waiter waiter;
struct ww_mutex *ww;
unsigned long flags;
int ret;
if (!use_ww_ctx)
@ -620,7 +621,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
return 0;
}
raw_spin_lock(&lock->wait_lock);
raw_spin_lock_irqsave(&lock->wait_lock, flags);
/*
* After waiting to acquire the wait_lock, try again.
*/
@ -681,7 +682,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
goto err;
}
raw_spin_unlock(&lock->wait_lock);
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
/* Make sure we do wakeups before calling schedule */
wake_up_q(&wake_q);
wake_q_init(&wake_q);
@ -706,9 +707,9 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
trace_contention_begin(lock, LCB_F_MUTEX);
}
raw_spin_lock(&lock->wait_lock);
raw_spin_lock_irqsave(&lock->wait_lock, flags);
}
raw_spin_lock(&lock->wait_lock);
raw_spin_lock_irqsave(&lock->wait_lock, flags);
acquired:
__set_current_state(TASK_RUNNING);
@ -734,7 +735,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
if (ww_ctx)
ww_mutex_lock_acquired(ww, ww_ctx);
raw_spin_unlock(&lock->wait_lock);
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
wake_up_q(&wake_q);
preempt_enable();
return 0;
@ -744,7 +745,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
__mutex_remove_waiter(lock, &waiter);
err_early_kill:
trace_contention_end(lock, ret);
raw_spin_unlock(&lock->wait_lock);
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
mutex_release(&lock->dep_map, ip);
wake_up_q(&wake_q);
@ -915,6 +916,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
struct task_struct *next = NULL;
DEFINE_WAKE_Q(wake_q);
unsigned long owner;
unsigned long flags;
mutex_release(&lock->dep_map, ip);
@ -941,7 +943,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
}
}
raw_spin_lock(&lock->wait_lock);
raw_spin_lock_irqsave(&lock->wait_lock, flags);
debug_mutex_unlock(lock);
if (!list_empty(&lock->wait_list)) {
/* get the first entry from the wait-list: */
@ -959,7 +961,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
__mutex_handoff(lock, next);
preempt_disable();
raw_spin_unlock(&lock->wait_lock);
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
wake_up_q(&wake_q);
preempt_enable();
}

21
kernel/locking/ww_mutex.h
View File

@ -70,14 +70,14 @@ __ww_mutex_has_waiters(struct mutex *lock)
return atomic_long_read(&lock->owner) & MUTEX_FLAG_WAITERS;
}
static inline void lock_wait_lock(struct mutex *lock)
static inline void lock_wait_lock(struct mutex *lock, unsigned long *flags)
{
raw_spin_lock(&lock->wait_lock);
raw_spin_lock_irqsave(&lock->wait_lock, *flags);
}
static inline void unlock_wait_lock(struct mutex *lock)
static inline void unlock_wait_lock(struct mutex *lock, unsigned long *flags)
{
raw_spin_unlock(&lock->wait_lock);
raw_spin_unlock_irqrestore(&lock->wait_lock, *flags);
}
static inline void lockdep_assert_wait_lock_held(struct mutex *lock)
@ -144,14 +144,14 @@ __ww_mutex_has_waiters(struct rt_mutex *lock)
return rt_mutex_has_waiters(&lock->rtmutex);
}
static inline void lock_wait_lock(struct rt_mutex *lock)
static inline void lock_wait_lock(struct rt_mutex *lock, unsigned long *flags)
{
raw_spin_lock(&lock->rtmutex.wait_lock);
raw_spin_lock_irqsave(&lock->rtmutex.wait_lock, *flags);
}
static inline void unlock_wait_lock(struct rt_mutex *lock)
static inline void unlock_wait_lock(struct rt_mutex *lock, unsigned long *flags)
{
raw_spin_unlock(&lock->rtmutex.wait_lock);
raw_spin_unlock_irqrestore(&lock->rtmutex.wait_lock, *flags);
}
static inline void lockdep_assert_wait_lock_held(struct rt_mutex *lock)
@ -380,6 +380,7 @@ static __always_inline void
ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
{
DEFINE_WAKE_Q(wake_q);
unsigned long flags;
ww_mutex_lock_acquired(lock, ctx);
@ -408,10 +409,10 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
* Uh oh, we raced in fastpath, check if any of the waiters need to
* die or wound us.
*/
lock_wait_lock(&lock->base);
lock_wait_lock(&lock->base, &flags);
__ww_mutex_check_waiters(&lock->base, ctx, &wake_q);
preempt_disable();
unlock_wait_lock(&lock->base);
unlock_wait_lock(&lock->base, &flags);
wake_up_q(&wake_q);
preempt_enable();
}