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 --- include/uapi/asm-generic/ipcbuf.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 include/uapi/asm-generic/ipcbuf.h (limited to 'include/uapi/asm-generic/ipcbuf.h') diff --git a/include/uapi/asm-generic/ipcbuf.h b/include/uapi/asm-generic/ipcbuf.h new file mode 100644 index 000000000..41a01b494 --- /dev/null +++ b/include/uapi/asm-generic/ipcbuf.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef __ASM_GENERIC_IPCBUF_H +#define __ASM_GENERIC_IPCBUF_H + +#include + +/* + * The generic ipc64_perm structure: + * Note extra padding because this structure is passed back and forth + * between kernel and user space. + * + * ipc64_perm was originally meant to be architecture specific, but + * everyone just ended up making identical copies without specific + * optimizations, so we may just as well all use the same one. + * + * Pad space is left for: + * - 32-bit mode_t on architectures that only had 16 bit + * - 32-bit seq + * - 2 miscellaneous 32-bit values + */ + +struct ipc64_perm { + __kernel_key_t key; + __kernel_uid32_t uid; + __kernel_gid32_t gid; + __kernel_uid32_t cuid; + __kernel_gid32_t cgid; + __kernel_mode_t mode; + /* pad if mode_t is u16: */ + unsigned char __pad1[4 - sizeof(__kernel_mode_t)]; + unsigned short seq; + unsigned short __pad2; + __kernel_ulong_t __unused1; + __kernel_ulong_t __unused2; +}; + +#endif /* __ASM_GENERIC_IPCBUF_H */ -- cgit v1.3.1