On Mon, Dec 14, 2020 at 11:56:52, Dan Carpenter
<dan.carpenter@xxxxxxxxxx> wrote:
> If the dw_edma_alloc_burst() function fails then we free "chunk" but
> it's still on the "desc->chunk->list" list so it will lead to a use
> after free. Also the "->chunks_alloc" count is incremented when it
> shouldn't be.
>
> In current kernels small allocations are guaranteed to succeed and
> dw_edma_alloc_burst() can't fail so this will not actually affect
> runtime.
>
> Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> Based on static analysis. Not tested.
>
> drivers/dma/dw-edma/dw-edma-core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index b971505b8715..08d71dafa001 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -86,12 +86,12 @@ static struct dw_edma_chunk *dw_edma_alloc_chunk(struct dw_edma_desc *desc)
>
> if (desc->chunk) {
> /* Create and add new element into the linked list */
> - desc->chunks_alloc++;
> - list_add_tail(&chunk->list, &desc->chunk->list);
> if (!dw_edma_alloc_burst(chunk)) {
> kfree(chunk);
> return NULL;
> }
> + desc->chunks_alloc++;
> + list_add_tail(&chunk->list, &desc->chunk->list);
> } else {
> /* List head */
> chunk->burst = NULL;
> --
> 2.29.2
Thanks for the fix! Nicely catch!
Acked-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
