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drm/amdkfd: Fix scheduler race in kfd_wait_on_events sleep loop

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Signed-off-by: Sean Keely <sean.keely@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
This commit is contained in:
Sean Keely 2017-10-27 19:35:21 -04:00 committed by Oded Gabbay
parent 1f9d09becb
commit d9aeec4cbb
1 changed files with 12 additions and 1 deletions
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13
drivers/gpu/drm/amd/amdkfd/kfd_events.c
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@ -806,6 +806,17 @@ int kfd_wait_on_events(struct kfd_process *p,
break;
}
/* Set task state to interruptible sleep before
* checking wake-up conditions. A concurrent wake-up
* will put the task back into runnable state. In that
* case schedule_timeout will not put the task to
* sleep and we'll get a chance to re-check the
* updated conditions almost immediately. Otherwise,
* this race condition would lead to a soft hang or a
* very long sleep.
*/
set_current_state(TASK_INTERRUPTIBLE);
if (test_event_condition(all, num_events, event_waiters)) {
if (copy_signaled_event_data(num_events,
event_waiters, events))
@ -820,7 +831,7 @@ int kfd_wait_on_events(struct kfd_process *p,
break;
}
timeout = schedule_timeout_interruptible(timeout);
timeout = schedule_timeout(timeout);
}
__set_current_state(TASK_RUNNING);