[PATCH 6.18 040/122] drm/xe: Skip address copy for sync-only execs

Greg Kroah-Hartman
2026-02-04T15:30:07Z

From: Shuicheng Lin <shuicheng.lin@intel.com>

[ Upstream commit c73a8917b31e8ddbd53cc248e17410cec27f8f58 ]

For parallel exec queues, xe_exec_ioctl() copied the batch buffer address
array from userspace without checking num_batch_buffer.
If user creates a sync-only exec that doesn't use the address field, the
exec will fail with -EFAULT.
Add num_batch_buffer check to skip the copy, and the exec could be executed
successfully.

Here is the sync-only exec:
struct drm_xe_exec exec = {
.extensions = 0,
.exec_queue_id = qid,
.num_syncs = 1,
.syncs = (uintptr_t)&sync,
.address = 0, /* ignored for sync-only */
.num_batch_buffer = 0, /* sync-only */
};

Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260122214053.3189366-2-shuicheng.lin@intel.com
(cherry picked from commit 4761791c1e736273d612ff564f318bfbbb04fa4e)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/xe/xe_exec.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c
index ca85f7c15fabe..87a32b61bece6 100644
--- a/drivers/gpu/drm/xe/xe_exec.c
+++ b/drivers/gpu/drm/xe/xe_exec.c
@@ -182,9 +182,9 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
goto err_syncs;
}

- if (xe_exec_queue_is_parallel(q)) {
- err = copy_from_user(addresses, addresses_user, sizeof(u64) *
- q->width);
+ if (args->num_batch_buffer && xe_exec_queue_is_parallel(q)) {
+ err = copy_from_user(addresses, addresses_user,
+ sizeof(u64) * q->width);
if (err) {
err = -EFAULT;
goto err_syncs;
--
2.51.0