diff options
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b583141c5481..33f1106b4f99 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -864,8 +864,17 @@ void wq_worker_running(struct task_struct *task) if (!worker->sleeping) return; + + /* + * If preempted by unbind_workers() between the WORKER_NOT_RUNNING check + * and the nr_running increment below, we may ruin the nr_running reset + * and leave with an unexpected pool->nr_running == 1 on the newly unbound + * pool. Protect against such race. + */ + preempt_disable(); if (!(worker->flags & WORKER_NOT_RUNNING)) atomic_inc(&worker->pool->nr_running); + preempt_enable(); worker->sleeping = 0; } @@ -899,6 +908,16 @@ void wq_worker_sleeping(struct task_struct *task) raw_spin_lock_irq(&pool->lock); /* + * Recheck in case unbind_workers() preempted us. We don't + * want to decrement nr_running after the worker is unbound + * and nr_running has been reset. + */ + if (worker->flags & WORKER_NOT_RUNNING) { + raw_spin_unlock_irq(&pool->lock); + return; + } + + /* * The counterpart of the following dec_and_test, implied mb, * worklist not empty test sequence is in insert_work(). * Please read comment there. @@ -1526,7 +1545,8 @@ out: * @work: work to queue * * We queue the work to a specific CPU, the caller must ensure it - * can't go away. + * can't go away. Callers that fail to ensure that the specified + * CPU cannot go away will execute on a randomly chosen CPU. * * Return: %false if @work was already on a queue, %true otherwise. */ |