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/testing/radix-tree/regression4.c | 79 ++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 tools/testing/radix-tree/regression4.c (limited to 'tools/testing/radix-tree/regression4.c') diff --git a/tools/testing/radix-tree/regression4.c b/tools/testing/radix-tree/regression4.c new file mode 100644 index 000000000..cf4e5aba6 --- /dev/null +++ b/tools/testing/radix-tree/regression4.c @@ -0,0 +1,79 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "regression.h" + +static pthread_barrier_t worker_barrier; +static int obj0, obj1; +static RADIX_TREE(mt_tree, GFP_KERNEL); + +static void *reader_fn(void *arg) +{ + int i; + void *entry; + + rcu_register_thread(); + pthread_barrier_wait(&worker_barrier); + + for (i = 0; i < 1000000; i++) { + rcu_read_lock(); + entry = radix_tree_lookup(&mt_tree, 0); + rcu_read_unlock(); + if (entry != &obj0) { + printf("iteration %d bad entry = %p\n", i, entry); + abort(); + } + } + + rcu_unregister_thread(); + + return NULL; +} + +static void *writer_fn(void *arg) +{ + int i; + + rcu_register_thread(); + pthread_barrier_wait(&worker_barrier); + + for (i = 0; i < 1000000; i++) { + radix_tree_insert(&mt_tree, 1, &obj1); + radix_tree_delete(&mt_tree, 1); + } + + rcu_unregister_thread(); + + return NULL; +} + +void regression4_test(void) +{ + pthread_t reader, writer; + + printv(1, "regression test 4 starting\n"); + + radix_tree_insert(&mt_tree, 0, &obj0); + pthread_barrier_init(&worker_barrier, NULL, 2); + + if (pthread_create(&reader, NULL, reader_fn, NULL) || + pthread_create(&writer, NULL, writer_fn, NULL)) { + perror("pthread_create"); + exit(1); + } + + if (pthread_join(reader, NULL) || pthread_join(writer, NULL)) { + perror("pthread_join"); + exit(1); + } + + printv(1, "regression test 4 passed\n"); +} -- cgit v1.3.1