Am 27.10.22 um 00:46 schrieb Dmitry Osipenko:
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]>
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]>
It would be even cleaner if we completely drop the dmabuf parameter for
the function and just use the inside the attachment.
Anyway patch is Reviewed-by: Christian König <[email protected]>
for now, wider cleanups can come later on.
Regards,
Christian.
---
drivers/dma-buf/dma-buf.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index c40d72d318fd..6e33ef4fde34 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -998,9 +998,10 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct
dma_buf_attachment *attach)
if (WARN_ON(!dmabuf || !attach))
return;
- dma_resv_lock(attach->dmabuf->resv, NULL);
+ dma_resv_lock(dmabuf->resv, NULL);
if (attach->sgt) {
+ WARN_ON(dmabuf != attach->dmabuf);
__unmap_dma_buf(attach, attach->sgt, attach->dir);
