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 --- tools/lib/subcmd/subcmd-util.h | 75 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 tools/lib/subcmd/subcmd-util.h (limited to 'tools/lib/subcmd/subcmd-util.h') diff --git a/tools/lib/subcmd/subcmd-util.h b/tools/lib/subcmd/subcmd-util.h new file mode 100644 index 000000000..c742b0881 --- /dev/null +++ b/tools/lib/subcmd/subcmd-util.h @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __SUBCMD_UTIL_H +#define __SUBCMD_UTIL_H + +#include +#include +#include +#include + +static inline void report(const char *prefix, const char *err, va_list params) +{ + char msg[1024]; + vsnprintf(msg, sizeof(msg), err, params); + fprintf(stderr, " %s%s\n", prefix, msg); +} + +static __noreturn inline void die(const char *err, ...) +{ + va_list params; + + va_start(params, err); + report(" Fatal: ", err, params); + va_end(params); + exit(128); +} + +#define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) + +#define alloc_nr(x) (((x)+16)*3/2) + +/* + * Realloc the buffer pointed at by variable 'x' so that it can hold + * at least 'nr' entries; the number of entries currently allocated + * is 'alloc', using the standard growing factor alloc_nr() macro. + * + * DO NOT USE any expression with side-effect for 'x' or 'alloc'. + */ +#define ALLOC_GROW(x, nr, alloc) \ + do { \ + if ((nr) > alloc) { \ + if (alloc_nr(alloc) < (nr)) \ + alloc = (nr); \ + else \ + alloc = alloc_nr(alloc); \ + x = xrealloc((x), alloc * sizeof(*(x))); \ + } \ + } while(0) + +static inline void *xrealloc(void *ptr, size_t size) +{ + void *ret = realloc(ptr, size); + if (!ret) + die("Out of memory, realloc failed"); + return ret; +} + +#define astrcatf(out, fmt, ...) \ +({ \ + char *tmp = *(out); \ + if (asprintf((out), "%s" fmt, tmp ?: "", ## __VA_ARGS__) == -1) \ + die("asprintf failed"); \ + free(tmp); \ +}) + +static inline void astrcat(char **out, const char *add) +{ + char *tmp = *out; + + if (asprintf(out, "%s%s", tmp ?: "", add) == -1) + die("asprintf failed"); + + free(tmp); +} + +#endif /* __SUBCMD_UTIL_H */ -- cgit v1.3.1