diff options
Diffstat (limited to 'kernel/locking/mutex.c')
| -rw-r--r-- | kernel/locking/mutex.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index a39ecccbd106..e2f59863a866 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -644,6 +644,8 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas goto err_early_kill; } + WARN_ON(current->blocked_on); + current->blocked_on = lock; set_current_state(state); trace_contention_begin(lock, LCB_F_MUTEX); for (;;) { @@ -680,6 +682,12 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas first = __mutex_waiter_is_first(lock, &waiter); + /* + * As we likely have been woken up by task + * that has cleared our blocked_on state, re-set + * it to the lock we are trying to aquire. + */ + current->blocked_on = lock; set_current_state(state); /* * Here we order against unlock; we must either see it change @@ -691,8 +699,11 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas if (first) { trace_contention_begin(lock, LCB_F_MUTEX | LCB_F_SPIN); + /* clear blocked_on as mutex_optimistic_spin may schedule() */ + current->blocked_on = NULL; if (mutex_optimistic_spin(lock, ww_ctx, &waiter)) break; + current->blocked_on = lock; trace_contention_begin(lock, LCB_F_MUTEX); } @@ -700,6 +711,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas } raw_spin_lock_irqsave(&lock->wait_lock, flags); acquired: + current->blocked_on = NULL; __set_current_state(TASK_RUNNING); if (ww_ctx) { @@ -729,9 +741,11 @@ skip_wait: return 0; err: + current->blocked_on = NULL; __set_current_state(TASK_RUNNING); __mutex_remove_waiter(lock, &waiter); err_early_kill: + WARN_ON(current->blocked_on); trace_contention_end(lock, ret); raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q); debug_mutex_free_waiter(&waiter); @@ -942,6 +956,14 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne next = waiter->task; debug_mutex_wake_waiter(lock, waiter); + /* + * Unlock wakeups can be happening in parallel + * (when optimistic spinners steal and release + * the lock), so blocked_on may already be + * cleared here. + */ + WARN_ON(next->blocked_on && next->blocked_on != lock); + next->blocked_on = NULL; wake_q_add(&wake_q, next); } |