dma-buf: fix an error pointer vs NULL bug

Smatch detected potential error pointer dereference. drivers/gpu/drm/drm_syncobj.c:888 drm_syncobj_transfer_to_timeline() error: 'fence' dereferencing possible ERR_PTR() The error pointer comes from dma_fence_allocate_private_stub(). One caller expected error pointers and one expected NULL pointers. Change it to return NULL and update the caller which expected error pointers, drm_syncobj_assign_null_handle(), to check for NULL instead. Fixes: f781f66 ("dma-buf: keep the signaling time of merged fences v3") Signed-off-by: Dan Carpenter <[email protected]> Reviewed-by: Christian König <[email protected]> Reviewed-by: Sumit Semwal <[email protected]> Signed-off-by: Sumit Semwal <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
wafgo · Jul 6, 2023 · 00ae149 · 00ae149
1 parent 7f34e01
commit 00ae149
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Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
@@ -160,7 +160,7 @@ struct dma_fence *dma_fence_allocate_private_stub(ktime_t timestamp)
 
 	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
 	if (fence == NULL)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	dma_fence_init(fence,
 		       &dma_fence_stub_ops,

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
@@ -355,8 +355,8 @@ static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
 {
 	struct dma_fence *fence = dma_fence_allocate_private_stub(ktime_get());
 
-	if (IS_ERR(fence))
-		return PTR_ERR(fence);
+	if (!fence)
+		return -ENOMEM;
 
 	drm_syncobj_replace_fence(syncobj, fence);
 	dma_fence_put(fence);