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 --- drivers/md/bcache/debug.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 drivers/md/bcache/debug.h (limited to 'drivers/md/bcache/debug.h') diff --git a/drivers/md/bcache/debug.h b/drivers/md/bcache/debug.h new file mode 100644 index 000000000..fb3d4dff4 --- /dev/null +++ b/drivers/md/bcache/debug.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _BCACHE_DEBUG_H +#define _BCACHE_DEBUG_H + +struct bio; +struct cached_dev; +struct cache_set; + +#ifdef CONFIG_BCACHE_DEBUG + +void bch_btree_verify(struct btree *b); +void bch_data_verify(struct cached_dev *dc, struct bio *bio); + +#define expensive_debug_checks(c) ((c)->expensive_debug_checks) +#define key_merging_disabled(c) ((c)->key_merging_disabled) +#define bypass_torture_test(d) ((d)->bypass_torture_test) + +#else /* DEBUG */ + +static inline void bch_btree_verify(struct btree *b) {} +static inline void bch_data_verify(struct cached_dev *dc, struct bio *bio) {} + +#define expensive_debug_checks(c) 0 +#define key_merging_disabled(c) 0 +#define bypass_torture_test(d) 0 + +#endif + +#ifdef CONFIG_DEBUG_FS +void bch_debug_init_cache_set(struct cache_set *c); +#else +static inline void bch_debug_init_cache_set(struct cache_set *c) {} +#endif + +#endif -- cgit v1.3.1