Re: [PATCH v1 1/2] drm/amdgpu/userq: Only look up for gem objects when count is non zero

[Khatri, Sunil]

On 13-03-2026 02:09 pm, Tvrtko Ursulin wrote:

On 10/03/2026 13:55, Sunil Khatri wrote:
In function amdgpu_userq_wait_ioctl, call function 
drm_gem_objects_lookup
only if the count is valid i.e non zero.

In case of object count is 0 set the pointer to NULL for proper clean
up.

Hasn't this been discussed already with the conclusion that nothing is 
broken? Or I am missing something?
Regards,

Tvrtko
Issue was seen again since Alex pulled 6.19 fixes from DRM and the 
drm_gem_objects_lookup again got reverted to old and we started to see 
the issue. With that in mind Alex too suggested that nothing wrong if we 
explicitly check in driver too. Also i thought its only when handles are 
Zero case when the problem is actually seen and why not that have a 
check targeting that and not to invoke the function 
drm_gem_objects_lookup itself for that specific case.

Regards
Sunil Khatri

Signed-off-by: Sunil Khatri <sunil.kha...@amd.com>
---
  .../gpu/drm/amd/amdgpu/amdgpu_userq_fence.c   | 32 ++++++++++++-------
  1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
index 76f32fd768fb..a4fff90b190a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
@@ -665,19 +665,27 @@ int amdgpu_userq_wait_ioctl(struct drm_device 
*dev, void *data,
          goto free_timeline_handles;
      }
  -    r = drm_gem_objects_lookup(filp,
- u64_to_user_ptr(wait_info->bo_read_handles),
-                   num_read_bo_handles,
-                   &gobj_read);
-    if (r)
-        goto free_timeline_points;
+    if (num_read_bo_handles) {
+        r = drm_gem_objects_lookup(filp,
+ u64_to_user_ptr(wait_info->bo_read_handles),
+                       num_read_bo_handles,
+                       &gobj_read);
+        if (r)
+            goto free_timeline_points;
+    } else {
+        gobj_read = NULL;
+    }
  -    r = drm_gem_objects_lookup(filp,
- u64_to_user_ptr(wait_info->bo_write_handles),
-                   num_write_bo_handles,
-                   &gobj_write);
-    if (r)
-        goto put_gobj_read;
+    if (num_write_bo_handles) {
+        r = drm_gem_objects_lookup(filp,
+ u64_to_user_ptr(wait_info->bo_write_handles),
+                       num_write_bo_handles,
+                       &gobj_write);
+        if (r)
+            goto put_gobj_read;
+    } else {
+        gobj_write = NULL;
+    }
        drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT,
                (num_read_bo_handles + num_write_bo_handles));