From d72312d730450aab225a80bc84436757b85b08b5 Mon Sep 17 00:00:00 2001 From: Tomasz Lis Date: Mon, 24 Nov 2025 23:28:53 +0100 Subject: [PATCH] drm/xe: Protect against unset LRC when pausing submissions MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit While pausing submissions, it is possible to encouner an exec queue which is during creation, and therefore doesn't have a valid xe_lrc struct reference. Protect agains such situation, by checking for NULL before access. Reviewed-by: Matthew Brost Fixes: c25c1010df88 ("drm/xe/vf: Replay GuC submission state on pause / unpause") Signed-off-by: Tomasz Lis Signed-off-by: Matthew Brost Link: https://patch.msgid.link/20251124222853.1900800-1-tomasz.lis@intel.com (cherry picked from commit 07cf4b864f523f01d2bb522a05813df30b076ba8) Signed-off-by: Thomas Hellström --- drivers/gpu/drm/xe/xe_guc_submit.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c index c56fd44641f6..ed7be50b2f72 100644 --- a/drivers/gpu/drm/xe/xe_guc_submit.c +++ b/drivers/gpu/drm/xe/xe_guc_submit.c @@ -2112,6 +2112,18 @@ static void guc_exec_queue_revert_pending_state_change(struct xe_guc *guc, q->guc->resume_time = 0; } +static void lrc_parallel_clear(struct xe_lrc *lrc) +{ + struct xe_device *xe = gt_to_xe(lrc->gt); + struct iosys_map map = xe_lrc_parallel_map(lrc); + int i; + + for (i = 0; i < WQ_SIZE / sizeof(u32); ++i) + parallel_write(xe, map, wq[i], + FIELD_PREP(WQ_TYPE_MASK, WQ_TYPE_NOOP) | + FIELD_PREP(WQ_LEN_MASK, 0)); +} + /* * This function is quite complex but only real way to ensure no state is lost * during VF resume flows. The function scans the queue state, make adjustments @@ -2135,8 +2147,8 @@ static void guc_exec_queue_pause(struct xe_guc *guc, struct xe_exec_queue *q) guc_exec_queue_revert_pending_state_change(guc, q); if (xe_exec_queue_is_parallel(q)) { - struct xe_device *xe = guc_to_xe(guc); - struct iosys_map map = xe_lrc_parallel_map(q->lrc[0]); + /* Pairs with WRITE_ONCE in __xe_exec_queue_init */ + struct xe_lrc *lrc = READ_ONCE(q->lrc[0]); /* * NOP existing WQ commands that may contain stale GGTT @@ -2144,10 +2156,8 @@ static void guc_exec_queue_pause(struct xe_guc *guc, struct xe_exec_queue *q) * seems to get confused if the WQ head/tail pointers are * adjusted. */ - for (i = 0; i < WQ_SIZE / sizeof(u32); ++i) - parallel_write(xe, map, wq[i], - FIELD_PREP(WQ_TYPE_MASK, WQ_TYPE_NOOP) | - FIELD_PREP(WQ_LEN_MASK, 0)); + if (lrc) + lrc_parallel_clear(lrc); } job = xe_sched_first_pending_job(sched); -- 2.47.3