dma-buf: Fix NULL pointer dereference in sanitycheck()

[ Upstream commit 2295bd846765c766701e666ed2e4b35396be25e6 ]

If due to a memory allocation failure mock_chain() returns NULL, it is
passed to dma_fence_enable_sw_signaling() resulting in NULL pointer
dereference there.

Call dma_fence_enable_sw_signaling() only if mock_chain() succeeds.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: d62c43a953ce ("dma-buf: Enable signaling on fence for selftests")
Signed-off-by: Pavel Sakharov <p.sakharov@ispras.ru>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240319231527.1821372-1-p.sakharov@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/dma-buf/st-dma-fence-chain.c b/drivers/dma-buf/st-dma-fence-chain.c
index 9c2a0c082a768f89ddba627e6a5d61edac512f1b..ed4b323886e430847dcb02dd916793adda0c18ea 100644 (file)
--- a/drivers/dma-buf/st-dma-fence-chain.c
+++ b/drivers/dma-buf/st-dma-fence-chain.c
@@ -84,11 +84,11 @@ static int sanitycheck(void *arg)
                return -ENOMEM;
 
        chain = mock_chain(NULL, f, 1);
-       if (!chain)
+       if (chain)
+               dma_fence_enable_sw_signaling(chain);
+       else
                err = -ENOMEM;
 
-       dma_fence_enable_sw_signaling(chain);
-
        dma_fence_signal(f);
        dma_fence_put(f);