6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chen Ridong <chenridong@xxxxxxxxxx> commit c43ec96e8d34399bd9dab2f2dc316b904892133f upstream. The at_xdmac_memset_create_desc may return NULL, which will lead to a null pointer dereference. For example, the len input is error, or the atchan->free_descs_list is empty and memory is exhausted. Therefore, add check to avoid this. Fixes: b206d9a23ac7 ("dmaengine: xdmac: Add memset support") Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx> Link: https://lore.kernel.org/r/20241029082845.1185380-1-chenridong@xxxxxxxxxxxxxxx Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/dma/at_xdmac.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -1287,6 +1287,8 @@ at_xdmac_prep_dma_memset(struct dma_chan return NULL; desc = at_xdmac_memset_create_desc(chan, atchan, dest, len, value); + if (!desc) + return NULL; list_add_tail(&desc->desc_node, &desc->descs_list); desc->tx_dma_desc.cookie = -EBUSY;