[PATCH] media: exynos4-is: fix DMA memory double free

[Guangshuo Li <lgs201920130244@gmail.com>]

fimc_is_alloc_cpu_memory() frees the coherent DMA buffer when its
DMA address does not satisfy the firmware alignment requirement,
but leaves is->memory.vaddr non-NULL.

Because firmware loading is asynchronous, this error path may run
after probe has returned successfully. A later remove can then
attempt to free the same DMA allocation again.

Set is->memory.vaddr to NULL after freeing the buffer so the
existing NULL check in fimc_is_free_cpu_memory() skips the
already-freed allocation.

This issue was found by our static analysis tool under development.

Fixes: db47622c13ae ("media: platform: exynos4-is: remove all references to physical addresses")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/media/platform/samsung/exynos4-is/fimc-is.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/media/platform/samsung/exynos4-is/fimc-is.c b/drivers/media/platform/samsung/exynos4-is/fimc-is.c
index b7d9bfedd590..9fdc352abfe4 100644
--- a/drivers/media/platform/samsung/exynos4-is/fimc-is.c
+++ b/drivers/media/platform/samsung/exynos4-is/fimc-is.c
@@ -346,6 +346,7 @@ static int fimc_is_alloc_cpu_memory(struct fimc_is *is)
 			(u32)is->memory.addr);
 		dma_free_coherent(dev, is->memory.size, is->memory.vaddr,
 				  is->memory.addr);
+		is->memory.vaddr = NULL;
 		return -EIO;
 	}
 
-- 
2.43.0