Am 28.10.25 um 04:43 schrieb Chintan Patel:
Currently, wait_event_timeout() in drm_wait_one_vblank() uses a 100ms timeout. Under heavy scheduling pressure or rare delayed vblank handling, this can trigger WARNs unnecessarily. Increase the timeout to 1000ms to reduce spurious WARNs, while still catching genuine issues.
Thanks a lot.
Reported-by: [email protected] Closes: https://syzkaller.appspot.com/bug?extid=147ba789658184f0ce04 Tested-by: [email protected] Signed-off-by: Chintan Patel <[email protected]>
Reviewed-by: Thomas Zimmermann <[email protected]>
v2: - Dropped unnecessary in-code comment (suggested by Thomas Zimmermann) - Removed else branch, only log timeout case v3: - Replaced drm_dbg_kms()/manual logging with drm_err() (suggested by Ville Syrjälä) - Removed unnecessary curr = drm_vblank_count() (suggested by Thomas Zimmermann) - Fixed commit message wording ("invalid userspace calls" → "delayed vblank handling") v4: - Keep the original drm_WARN() to catch genuine kernel issues - Increased timeout from 100ms → 1000ms to reduce spurious WARNs (suggested by Thomas Zimmermann) --- drivers/gpu/drm/drm_vblank.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 46f59883183d..f779103b261b 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -1303,7 +1303,7 @@ void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)ret = wait_event_timeout(vblank->queue,last != drm_vblank_count(dev, pipe), - msecs_to_jiffies(100)); + msecs_to_jiffies(1000));drm_WARN(dev, ret == 0, "vblank wait timed out on crtc %i\n", pipe);
-- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)
