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Commit 1d377ca6 authored by Lynus Vaz's avatar Lynus Vaz
Browse files

msm: kgsl: Avoid a deadlock with the cmdbatch timer 



Don't take the cmdbatch lock while deleting the cmdbatch timer.
This avoids a deadlock where del_timer_sync() waits for the timer
function which needs to take the lock.

CRs-Fixed: 644944
Change-Id: Iaeb5a26b67e96e8e748fb9ff8c26fa8b0f2c3827
Signed-off-by: default avatarLynus Vaz <lvaz@codeaurora.org>
parent 3a86fb3f

drivers/gpu/msm/adreno_dispatch.c

+2 −1
Original line number Diff line number Diff line
@@ -181,14 +181,15 @@ static inline struct kgsl_cmdbatch *adreno_dispatcher_get_cmdbatch( 
			 */

			if (!timer_pending(&cmdbatch->timer))

				mod_timer(&cmdbatch->timer, jiffies + (5 * HZ));

			spin_unlock(&cmdbatch->lock);

		} else {

			/*

			 * Otherwise, delete the timer to make sure it is good

			 * and dead before queuing the buffer

			 */

			spin_unlock(&cmdbatch->lock);

			del_timer_sync(&cmdbatch->timer);

		}

		spin_unlock(&cmdbatch->lock);



		if (pending) {

			cmdbatch = ERR_PTR(-EAGAIN);

drivers/gpu/msm/kgsl.c

+9 −10
Original line number Diff line number Diff line
@@ -1401,12 +1401,14 @@ static void _kgsl_cmdbatch_timer(unsigned long data) 
	if (cmdbatch == NULL || cmdbatch->context == NULL)

		return;



	spin_lock(&cmdbatch->lock);

	if (list_empty(&cmdbatch->synclist))

		goto done;



	pr_err("kgsl: possible gpu syncpoint deadlock for context %d timestamp %d\n",

		cmdbatch->context->id, cmdbatch->timestamp);

	pr_err(" Active sync points:\n");



	spin_lock(&cmdbatch->lock);



	/* Print all the pending sync objects */

	list_for_each_entry(event, &cmdbatch->synclist, node) {
@@ -1431,6 +1433,7 @@ static void _kgsl_cmdbatch_timer(unsigned long data) 
		}

	}



done:

	spin_unlock(&cmdbatch->lock);

}
@@ -1505,16 +1508,12 @@ static void kgsl_cmdbatch_sync_expire(struct kgsl_device *device, 
	}



	sched = list_empty(&event->cmdbatch->synclist) ? 1 : 0;

	spin_unlock(&event->cmdbatch->lock);



	/*

	 * If the list is empty delete the canary timer while

	 * still holding the lock

	 */

	/* If the list is empty delete the canary timer */

	if (sched)

		del_timer_sync(&event->cmdbatch->timer);



	spin_unlock(&event->cmdbatch->lock);



	/*

	 * if this is the last event in the list then tell

	 * the GPU device that the cmdbatch can be submitted
@@ -1569,11 +1568,11 @@ void kgsl_cmdbatch_destroy(struct kgsl_cmdbatch *cmdbatch) 
	LIST_HEAD(cancel_synclist);

	int sched = 0;



	spin_lock(&cmdbatch->lock);



	/* Zap the canary timer */

	del_timer_sync(&cmdbatch->timer);



	spin_lock(&cmdbatch->lock);



	/* Empty the synclist before canceling events */

	list_splice_init(&cmdbatch->synclist, &cancel_synclist);

	spin_unlock(&cmdbatch->lock);