From: Nicolas Ferre Date: Tue, 11 Sep 2012 15:21:45 +0000 (+0200) Subject: dmaengine: at_hdmac: check that each sg data length is non-null X-Git-Tag: firefly_0821_release~7541^2~664 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e24fd5136ca6d256900392565dfc895d5a2ed9b2;p=firefly-linux-kernel-4.4.55.git dmaengine: at_hdmac: check that each sg data length is non-null commit c456797681db814f4f5b36909e8e94047bf53d9c upstream. Avoid the construction of a malformed DMA request sent to the DMA controller. Log message is for debug only because this condition is unlikely to append and may only trigger at driver development time. Signed-off-by: Nicolas Ferre Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index fcccbdf9daf6..1357c3b1e3a2 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -702,6 +702,11 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); len = sg_dma_len(sg); + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), + "prep_slave_sg: sg(%d) data length is zero\n", i); + goto err; + } mem_width = 2; if (unlikely(mem & 3 || len & 3)) mem_width = 0; @@ -736,6 +741,11 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); len = sg_dma_len(sg); + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), + "prep_slave_sg: sg(%d) data length is zero\n", i); + goto err; + } mem_width = 2; if (unlikely(mem & 3 || len & 3)) mem_width = 0; @@ -769,6 +779,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, err_desc_get: dev_err(chan2dev(chan), "not enough descriptors available\n"); +err: atc_desc_put(atchan, first); return NULL; }