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Fri, 04 Sep 2026 23:29:04 -0700 (PDT) Received: from cachyos-x8664 ([177.245.224.138]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-47554d7bde7sm3881145fac.16.2026.09.04.23.29.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Sep 2026 23:29:03 -0700 (PDT) From: Diego Fernando Mancera Gomez To: Vinod Koul Cc: Binbin Zhou , Frank Li , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, Diego Fernando Mancera Gomez , stable@vger.kernel.org, "Claude Opus 4.8" Subject: [PATCH] dmaengine: loongson2-apb-cmc: fix descriptor leak in prep_slave_sg() Date: Sat, 5 Sep 2026 00:28:33 -0600 Message-ID: <20260905062833.272484-1-diegomancera.dev@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit loongson2_cmc_dma_prep_slave_sg() allocates the descriptor with kzalloc_flex() before iterating over the scatterlist. If loongson2_cmc_dma_set_xfer_param() fails inside the loop, the function returns ERR_PTR(ret) without freeing the descriptor. At this point the descriptor has not been handed to vchan_tx_prep() yet, so nothing else will ever free it, leaking it on every failed ->device_prep_slave_sg() call (e.g. an unsupported transfer direction or bus width). The neighbouring error path for the num_items check already frees the descriptor before returning; do the same on the set_xfer_param() failure path. Fixes: 1c0028e725f1 ("dmaengine: loongson: New driver for the Loongson Multi-Channel DMA controller") Link: https://lore.kernel.org/all/20260818094957.7D2221F000E9@smtp.kernel.org/ Cc: stable@vger.kernel.org Signed-off-by: Diego Fernando Mancera Gomez Co-authored-by: Claude Opus 4.8 Claude-Session: https://claude.ai/code/session_012bUV3WshMSfTq61n1cgh1i --- drivers/dma/loongson/loongson2-apb-cmc-dma.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/dma/loongson/loongson2-apb-cmc-dma.c b/drivers/dma/loongson/loongson2-apb-cmc-dma.c index 1c9a542edc85..60eb4d961610 100644 --- a/drivers/dma/loongson/loongson2-apb-cmc-dma.c +++ b/drivers/dma/loongson/loongson2-apb-cmc-dma.c @@ -404,8 +404,10 @@ loongson2_cmc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, for_each_sg(sgl, sg, sg_len, i) { ret = loongson2_cmc_dma_set_xfer_param(lchan, direction, &buswidth, sg_dma_len(sg)); - if (ret) + if (ret) { + kfree(desc); return ERR_PTR(ret); + } num_items = DIV_ROUND_UP(sg_dma_len(sg), buswidth); if (num_items >= LOONSON2_CMCDMA_MAX_DATA_ITEMS) { -- 2.55.0