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/msgbuf.h | 49 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 include/uapi/asm-generic/msgbuf.h (limited to 'include/uapi/asm-generic/msgbuf.h') diff --git a/include/uapi/asm-generic/msgbuf.h b/include/uapi/asm-generic/msgbuf.h new file mode 100644 index 000000000..6504d7b74 --- /dev/null +++ b/include/uapi/asm-generic/msgbuf.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef __ASM_GENERIC_MSGBUF_H +#define __ASM_GENERIC_MSGBUF_H + +#include +#include + +/* + * generic msqid64_ds structure. + * + * Note extra padding because this structure is passed back and forth + * between kernel and user space. + * + * msqid64_ds 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. + * + * 64 bit architectures use a 64-bit long time field here, while + * 32 bit architectures have a pair of unsigned long values. + * On big-endian systems, the lower half is in the wrong place. + * + * Pad space is left for: + * - 2 miscellaneous 32-bit values + */ + +struct msqid64_ds { + struct ipc64_perm msg_perm; +#if __BITS_PER_LONG == 64 + long msg_stime; /* last msgsnd time */ + long msg_rtime; /* last msgrcv time */ + long msg_ctime; /* last change time */ +#else + unsigned long msg_stime; /* last msgsnd time */ + unsigned long msg_stime_high; + unsigned long msg_rtime; /* last msgrcv time */ + unsigned long msg_rtime_high; + unsigned long msg_ctime; /* last change time */ + unsigned long msg_ctime_high; +#endif + unsigned long msg_cbytes; /* current number of bytes on queue */ + unsigned long msg_qnum; /* number of messages in queue */ + unsigned long msg_qbytes; /* max number of bytes on queue */ + __kernel_pid_t msg_lspid; /* pid of last msgsnd */ + __kernel_pid_t msg_lrpid; /* last receive pid */ + unsigned long __unused4; + unsigned long __unused5; +}; + +#endif /* __ASM_GENERIC_MSGBUF_H */ -- cgit v1.3.1