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 --- arch/powerpc/boot/string.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 arch/powerpc/boot/string.h (limited to 'arch/powerpc/boot/string.h') diff --git a/arch/powerpc/boot/string.h b/arch/powerpc/boot/string.h new file mode 100644 index 000000000..2b28d1853 --- /dev/null +++ b/arch/powerpc/boot/string.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _PPC_BOOT_STRING_H_ +#define _PPC_BOOT_STRING_H_ +#include + +extern char *strcpy(char *dest, const char *src); +extern char *strcat(char *dest, const char *src); +extern char *strchr(const char *s, int c); +extern char *strrchr(const char *s, int c); +extern int strcmp(const char *s1, const char *s2); +extern int strncmp(const char *s1, const char *s2, size_t n); +extern size_t strlen(const char *s); +extern size_t strnlen(const char *s, size_t count); + +extern void *memset(void *s, int c, size_t n); +extern void *memmove(void *dest, const void *src, unsigned long n); +extern void *memcpy(void *dest, const void *src, unsigned long n); +extern void *memchr(const void *s, int c, size_t n); +extern int memcmp(const void *s1, const void *s2, size_t n); + +#endif /* _PPC_BOOT_STRING_H_ */ -- cgit v1.3.1