From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- rust/helpers/dma.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 rust/helpers/dma.c (limited to 'rust/helpers/dma.c') diff --git a/rust/helpers/dma.c b/rust/helpers/dma.c new file mode 100644 index 000000000..9fbeb507b --- /dev/null +++ b/rust/helpers/dma.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +__rust_helper void *rust_helper_dma_alloc_attrs(struct device *dev, size_t size, + dma_addr_t *dma_handle, + gfp_t flag, unsigned long attrs) +{ + return dma_alloc_attrs(dev, size, dma_handle, flag, attrs); +} + +__rust_helper void rust_helper_dma_free_attrs(struct device *dev, size_t size, + void *cpu_addr, + dma_addr_t dma_handle, + unsigned long attrs) +{ + dma_free_attrs(dev, size, cpu_addr, dma_handle, attrs); +} + +__rust_helper int rust_helper_dma_set_mask_and_coherent(struct device *dev, + u64 mask) +{ + return dma_set_mask_and_coherent(dev, mask); +} + +__rust_helper int rust_helper_dma_set_mask(struct device *dev, u64 mask) +{ + return dma_set_mask(dev, mask); +} + +__rust_helper int rust_helper_dma_set_coherent_mask(struct device *dev, u64 mask) +{ + return dma_set_coherent_mask(dev, mask); +} + +__rust_helper int rust_helper_dma_map_sgtable(struct device *dev, struct sg_table *sgt, + enum dma_data_direction dir, unsigned long attrs) +{ + return dma_map_sgtable(dev, sgt, dir, attrs); +} + +__rust_helper size_t rust_helper_dma_max_mapping_size(struct device *dev) +{ + return dma_max_mapping_size(dev); +} + +__rust_helper void rust_helper_dma_set_max_seg_size(struct device *dev, + unsigned int size) +{ + dma_set_max_seg_size(dev, size); +} -- cgit v1.3.1