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* [PATCH v1 1/1] drm/xe/guc: Fix wake_up race in handle_sched_done
@ 2026-08-26  9:33 Jakub Legowski
  2026-08-26  9:39 ` ✗ CI.checkpatch: warning for series starting with [v1,1/1] " Patchwork
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Jakub Legowski @ 2026-08-26  9:33 UTC (permalink / raw)
  To: intel-xe; +Cc: matthew.brost, maciej.patelczyk, Jakub Legowski

Move wake_up_all() after clear_exec_queue_pending_disable()

When a SCHED_DONE G2H arrives for a banned exec queue,
handle_sched_done() calls wake_up_all() before
clear_exec_queue_pending_disable(). This creates a race with the
wait_event_timeout() in guc_exec_queue_timedout_job() that waits
for pending_disable to be cleared:

    smp_rmb();
    ret = wait_event_timeout(guc->ct.wq,
                 ...
                 ...);

This was observed as:
[drm:guc_exec_queue_timedout_job [xe]] Tile0: GT0: Check job timeout: seqno=4294967169, lrc_seqno=4294967169, guc_id=4, running_time_ms=0, timeout_ms=5000, diff=0x00000001

Noving the wake_up_all() (along with its smp_wmb())
after all paths that clear pending_disable, ensuring that waiters
always observe the updated state when woken.

Same as for runnable_state == 1 in the beginning of
handle_sched_done().

Signed-off-by: Jakub Legowski <jakub.legowski@intel.com>
---
 drivers/gpu/drm/xe/xe_guc_submit.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
index 99d8c807ff05..2b86c2cde802 100644
--- a/drivers/gpu/drm/xe/xe_guc_submit.c
+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
@@ -3239,10 +3239,6 @@ static void handle_sched_done(struct xe_guc *guc, struct xe_exec_queue *q,
 			clear_exec_queue_pending_disable(q);
 			suspend_fence_signal(q);
 		} else {
-			if (exec_queue_banned(q)) {
-				smp_wmb();
-				wake_up_all(&guc->ct.wq);
-			}
 			if (exec_queue_destroyed(q)) {
 				/*
 				 * Make sure to clear the pending_disable only
@@ -3258,6 +3254,11 @@ static void handle_sched_done(struct xe_guc *guc, struct xe_exec_queue *q,
 			} else {
 				clear_exec_queue_pending_disable(q);
 			}
+			if (exec_queue_banned(q)) {
+				/* Pairs with the smp_rmb() in guc_exec_queue_timedout_job() */
+				smp_wmb();
+				wake_up_all(&guc->ct.wq);
+			}
 		}
 	}
 }
-- 
2.48.1

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^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-08-26 11:39 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-08-26  9:33 [PATCH v1 1/1] drm/xe/guc: Fix wake_up race in handle_sched_done Jakub Legowski
2026-08-26  9:39 ` ✗ CI.checkpatch: warning for series starting with [v1,1/1] " Patchwork
2026-08-26  9:40 ` ✓ CI.KUnit: success " Patchwork
2026-08-26  9:50 ` [PATCH v1 1/1] " sashiko-bot
2026-08-26 10:22 ` ✓ Xe.CI.BAT: success for series starting with [v1,1/1] " Patchwork
2026-08-26 11:39 ` ✗ Xe.CI.FULL: failure " Patchwork

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