When an out_fence_ptr is provided but DRM_MODE_PAGE_FLIP_EVENT is not
set, a drm_pending_vblank_event will be allocated. If later, there is an
allocation failure or another failure at setup_out_fence(), that event
will not have base.fence set and it will not be released at
complete_signaling().

Release the event and set crtc_state->event to NULL just like in the
DRM_MODE_PAGE_FLIP_EVENT case when there is a failure at
drm_event_reserve_init(). That is, prepare_signaling() releases the
event and there is nothing to be done at complete_signaling().

Reported-by: [email protected]
Closes: 
https://sashiko.dev/#/patchset/20260727-drm_crtc_atomic_commit_leak-v1-1-23d9948a9...@igalia.com?part=1
Signed-off-by: Thadeu Lima de Souza Cascardo <[email protected]>
---
 drivers/gpu/drm/drm_atomic_uapi.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c 
b/drivers/gpu/drm/drm_atomic_uapi.c
index 1050dddadb17..aca35fb4b1f9 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -1464,11 +1464,15 @@ static int prepare_signaling(struct drm_device *dev,
                if (fence_ptr) {
                        struct dma_fence *fence;
                        struct drm_out_fence_state *f;
+                       struct drm_pending_vblank_event *e = crtc_state->event;
 
                        f = krealloc(*fence_state, sizeof(**fence_state) *
                                     (*num_fences + 1), GFP_KERNEL);
-                       if (!f)
+                       if (!f) {
+                               kfree(e);
+                               crtc_state->event = NULL;
                                return -ENOMEM;
+                       }
 
                        memset(&f[*num_fences], 0, sizeof(*f));
 
@@ -1476,12 +1480,17 @@ static int prepare_signaling(struct drm_device *dev,
                        *fence_state = f;
 
                        fence = drm_crtc_create_fence(crtc);
-                       if (!fence)
+                       if (!fence) {
+                               kfree(e);
+                               crtc_state->event = NULL;
                                return -ENOMEM;
+                       }
 
                        ret = setup_out_fence(&f[(*num_fences)++], fence);
                        if (ret) {
                                dma_fence_put(fence);
+                               kfree(e);
+                               crtc_state->event = NULL;
                                return ret;
                        }
 

---
base-commit: df0311845915442ab75d03ee89fb443b444c1370
change-id: 20260728-drm_pending_vblank_event_leak-a36cedb296ba

Best regards,
--  
Thadeu Lima de Souza Cascardo <[email protected]>

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