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 --- tools/perf/util/threads.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 tools/perf/util/threads.h (limited to 'tools/perf/util/threads.h') diff --git a/tools/perf/util/threads.h b/tools/perf/util/threads.h new file mode 100644 index 000000000..da68d2223 --- /dev/null +++ b/tools/perf/util/threads.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __PERF_THREADS_H +#define __PERF_THREADS_H + +#include "hashmap.h" +#include "rwsem.h" + +struct thread; + +#define THREADS__TABLE_BITS 3 +#define THREADS__TABLE_SIZE (1 << THREADS__TABLE_BITS) + +struct threads_table_entry { + /* Key is tid, value is struct thread. */ + struct hashmap shard; + struct rw_semaphore lock; + struct thread *last_match; +}; + +struct threads { + struct threads_table_entry table[THREADS__TABLE_SIZE]; +}; + +void threads__init(struct threads *threads); +void threads__exit(struct threads *threads); +size_t threads__nr(struct threads *threads); +struct thread *threads__find(struct threads *threads, pid_t tid); +struct thread *threads__findnew(struct threads *threads, pid_t pid, pid_t tid, bool *created); +void threads__remove_all_threads(struct threads *threads); +void threads__remove(struct threads *threads, struct thread *thread); +int threads__for_each_thread(struct threads *threads, + int (*fn)(struct thread *thread, void *data), + void *data); + +#endif /* __PERF_THREADS_H */ -- cgit v1.3.1