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 --- lib/test_debug_virtual.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 lib/test_debug_virtual.c (limited to 'lib/test_debug_virtual.c') diff --git a/lib/test_debug_virtual.c b/lib/test_debug_virtual.c new file mode 100644 index 000000000..518ee8d21 --- /dev/null +++ b/lib/test_debug_virtual.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#ifdef CONFIG_MIPS +#include +#endif + +struct foo { + unsigned int bar; +}; + +static struct foo *foo; + +static int __init test_debug_virtual_init(void) +{ + phys_addr_t pa; + void *va; + + va = (void *)VMALLOC_START; + pa = virt_to_phys(va); + + pr_info("PA: %pa for VA: 0x%lx\n", &pa, (unsigned long)va); + + foo = kzalloc_obj(*foo); + if (!foo) + return -ENOMEM; + + pa = virt_to_phys(foo); + va = foo; + pr_info("PA: %pa for VA: 0x%lx\n", &pa, (unsigned long)va); + + return 0; +} +module_init(test_debug_virtual_init); + +static void __exit test_debug_virtual_exit(void) +{ + kfree(foo); +} +module_exit(test_debug_virtual_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Test module for CONFIG_DEBUG_VIRTUAL"); -- cgit v1.3.1