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/x86/boot/string.h | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 arch/x86/boot/string.h (limited to 'arch/x86/boot/string.h') diff --git a/arch/x86/boot/string.h b/arch/x86/boot/string.h new file mode 100644 index 000000000..4092bf2ed --- /dev/null +++ b/arch/x86/boot/string.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef BOOT_STRING_H +#define BOOT_STRING_H + +/* Undef any of these macros coming from string_32.h. */ +#undef memcpy +#undef memset +#undef memcmp + +void *memcpy(void *dst, const void *src, size_t len); +void *memmove(void *dst, const void *src, size_t len); +void *memset(void *dst, int c, size_t len); +int memcmp(const void *s1, const void *s2, size_t len); +int bcmp(const void *s1, const void *s2, size_t len); + +/* Access builtin version by default. */ +#define memcpy(d,s,l) __builtin_memcpy(d,s,l) +#define memset(d,c,l) __builtin_memset(d,c,l) +#define memcmp __builtin_memcmp + +extern int strcmp(const char *str1, const char *str2); +extern int strncmp(const char *cs, const char *ct, size_t count); +extern size_t strlen(const char *s); +extern char *strstr(const char *s1, const char *s2); +extern char *strchr(const char *s, int c); +extern size_t strnlen(const char *s, size_t maxlen); +extern unsigned long long simple_strtoull(const char *cp, char **endp, + unsigned int base); +long simple_strtol(const char *cp, char **endp, unsigned int base); + +int boot_kstrtoul(const char *s, unsigned int base, unsigned long *res); +#endif /* BOOT_STRING_H */ -- cgit v1.3.1