From 075bc7b1d3dde5ed43fbaabbc1a69f09b7fc3a47 Mon Sep 17 00:00:00 2001 From: Baineng Shou Date: Thu, 10 Sep 2026 10:16:52 +0800 Subject: [PATCH] dmaengine: mmp_pdma: fix wrong sg length in mmp_pdma_prep_slave_sg() In mmp_pdma_prep_slave_sg(), for_each_sg() iterates the scatterlist putting each entry into 'sg', but the entry length is read from 'sgl' (the list head) instead of 'sg' (the current entry): for_each_sg(sgl, sg, sg_len, i) { addr = sg_dma_address(sg); avail = sg_dma_len(sgl); /* should be 'sg' */ Consequently 'avail' is always the length of the first entry. For multi-sg lists this causes out-of-bounds reads when a later entry is shorter than the first, and silent data loss when it is longer. Single-sg or uniformly-sized lists happen to mask the issue. Fixes: c8acd6aa6bed3 ("dmaengine: mmp-pdma support") Signed-off-by: Baineng Shou Reviewed-by: Frank Li Link: https://patch.msgid.link/20260910021652.1296640-1-shoubaineng@gmail.com Signed-off-by: Vinod Koul --- drivers/dma/mmp_pdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c index 78e3e07e681d..ed520737882b 100644 --- a/drivers/dma/mmp_pdma.c +++ b/drivers/dma/mmp_pdma.c @@ -712,7 +712,7 @@ mmp_pdma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl, for_each_sg(sgl, sg, sg_len, i) { addr = sg_dma_address(sg); - avail = sg_dma_len(sgl); + avail = sg_dma_len(sg); do { len = min_t(size_t, avail, PDMA_MAX_DESC_BYTES);