Re: [PATCH v2 1/3] dmaengine: vchan: add vchan_chan_name() to get channel device name
From: sashiko-bot@kernel.org
Date: 2026-09-03 21:03:26
Also in:
dmaengine, imx, linux-sunxi
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: Pre-existing issues: - [High] This problem wasn't introduced by this patch, but there is a preexisting Use-After-Free of the channel name string in the IRQ handler registration on the probe error path. -- commit 33984ca85ddf2f8f41c22000aad40c8fceb5f946 Author: Frank Li [off-list ref] dmaengine: vchan: add vchan_chan_name() to get channel device name Introduce vchan_chan_name() to obtain the DMA channel device name. Use a dedicated helper instead of directly accessing dma_chan::dev so callers remain unaffected by an upcoming rename of the struct member. [ ... ]
quoted hunk ↗ jump to hunk
diff --git a/drivers/dma/stm32/stm32-dma.c b/drivers/dma/stm32/stm32-dma.c index d3ad78562a140..3e8151e2ad75a 100644 --- a/drivers/dma/stm32/stm32-dma.c +++ b/drivers/dma/stm32/stm32-dma.c@@ -1668,7 +1668,7 @@ static int stm32_dma_probe(struct platform_device *pdev) ret = devm_request_irq(&pdev->dev, chan->irq, stm32_dma_chan_irq, 0, - dev_name(chan2dev(chan)), chan); + vchan_chan_name(&chan->vchan), chan);
[Severity: High] This isn't a bug introduced by this patch, but is there a preexisting Use-After-Free of the channel name string in the IRQ handler registration on the probe error path? In stm32_dma_probe(), the driver successfully registers the DMA device using dma_async_device_register(), then iteratively allocates devres-managed IRQs using devm_request_irq() with the channel name pointer from vchan_chan_name(). If a subsequent operation fails (e.g. of_dma_controller_register()), the error handling path manually calls dma_async_device_unregister(dd). This frees the DMA device and its dynamically allocated channel name string immediately. However, the devres-managed IRQs remain active until the probe function returns and devres cleanup runs. During this window, the IRQ subsystem holds a dangling pointer to the freed channel name. Could this race window be triggered by unprivileged users concurrently reading /proc/interrupts, or if an interrupt fires during this time? -- Sashiko AI review · https://sashiko.dev/#/patchset/20260903-dma-chan_dev-rename-v2-0-0db305b6c716@nxp.com?part=1