The dma_buf_detach() locks attach->dmabuf->resv and then unlocks
dmabuf->resv, which could be a two different locks from a static
code checker perspective. In particular this triggers Smatch to
report the "double unlock" error. Make the locking pointers consistent.

Reported-by: Dan Carpenter <[email protected]>
Reviewed-by: Christian König <[email protected]>
Link: https://lore.kernel.org/dri-devel/Y1fLfsccW3AS%2Fo+%2F@kili/
Fixes: 809d9c72c2f8 ("dma-buf: Move dma_buf_attach() to dynamic locking 
specification")
Signed-off-by: Dmitry Osipenko <[email protected]>
---
 drivers/dma-buf/dma-buf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index c40d72d318fd..13bfd2d09c56 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -995,10 +995,10 @@ static void __unmap_dma_buf(struct dma_buf_attachment 
*attach,
  */
 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
 {
-       if (WARN_ON(!dmabuf || !attach))
+       if (WARN_ON(!dmabuf || !attach || dmabuf != attach->dmabuf))
                return;
 
-       dma_resv_lock(attach->dmabuf->resv, NULL);
+       dma_resv_lock(dmabuf->resv, NULL);
 
        if (attach->sgt) {
 
-- 
2.37.3

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