Merge branch 'for-3.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue fixes from Tejun Heo:
 "Two workqueue fixes.  One for an unlikely but possible critical bug
  during kworker shutdown and the other to make lockdep names a bit more
  descriptive"

* 'for-3.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: ensure @task is valid across kthread_stop()
  workqueue: add args to workqueue lockdep name

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 594521ba0d43f73e887375968006429c9ec19502..704f4f652d0af8b28406154678ee38b5f98298bf 100644 (file)
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -419,10 +419,7 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
        static struct lock_class_key __key;                             \
        const char *__lock_name;                                        \
                                                                        \
-       if (__builtin_constant_p(fmt))                                  \
-               __lock_name = (fmt);                                    \
-       else                                                            \
-               __lock_name = #fmt;                                     \
+       __lock_name = #fmt#args;                                        \
                                                                        \
        __alloc_workqueue_key((fmt), (flags), (max_active),             \
                              &__key, __lock_name, ##args);             \

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 82ef9f3b7473a81ef5004362c7281ae9f4aea82a..193e977a10eaeb6a7f9ca5927d08f558d68df434 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1851,6 +1851,12 @@ static void destroy_worker(struct worker *worker)
        if (worker->flags & WORKER_IDLE)
                pool->nr_idle--;
 
+       /*
+        * Once WORKER_DIE is set, the kworker may destroy itself at any
+        * point.  Pin to ensure the task stays until we're done with it.
+        */
+       get_task_struct(worker->task);
+
        list_del_init(&worker->entry);
        worker->flags |= WORKER_DIE;
 
@@ -1859,6 +1865,7 @@ static void destroy_worker(struct worker *worker)
        spin_unlock_irq(&pool->lock);
 
        kthread_stop(worker->task);
+       put_task_struct(worker->task);
        kfree(worker);
 
        spin_lock_irq(&pool->lock);