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/asm-generic/atomic64.h | 75 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 include/asm-generic/atomic64.h (limited to 'include/asm-generic/atomic64.h') diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h new file mode 100644 index 000000000..f22ccfc0d --- /dev/null +++ b/include/asm-generic/atomic64.h @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Generic implementation of 64-bit atomics using spinlocks, + * useful on processors that don't have 64-bit atomic instructions. + * + * Copyright © 2009 Paul Mackerras, IBM Corp. + */ +#ifndef _ASM_GENERIC_ATOMIC64_H +#define _ASM_GENERIC_ATOMIC64_H +#include + +typedef struct { + s64 __aligned(sizeof(s64)) counter; +} atomic64_t; + +#define ATOMIC64_INIT(i) { (i) } + +extern s64 generic_atomic64_read(const atomic64_t *v); +extern void generic_atomic64_set(atomic64_t *v, s64 i); + +#define ATOMIC64_OP(op) \ +extern void generic_atomic64_##op(s64 a, atomic64_t *v); + +#define ATOMIC64_OP_RETURN(op) \ +extern s64 generic_atomic64_##op##_return(s64 a, atomic64_t *v); + +#define ATOMIC64_FETCH_OP(op) \ +extern s64 generic_atomic64_fetch_##op(s64 a, atomic64_t *v); + +#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op) + +ATOMIC64_OPS(add) +ATOMIC64_OPS(sub) + +#undef ATOMIC64_OPS +#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_FETCH_OP(op) + +ATOMIC64_OPS(and) +ATOMIC64_OPS(or) +ATOMIC64_OPS(xor) + +#undef ATOMIC64_OPS +#undef ATOMIC64_FETCH_OP +#undef ATOMIC64_OP_RETURN +#undef ATOMIC64_OP + +extern s64 generic_atomic64_dec_if_positive(atomic64_t *v); +extern s64 generic_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n); +extern s64 generic_atomic64_xchg(atomic64_t *v, s64 new); +extern s64 generic_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u); + +#define arch_atomic64_read generic_atomic64_read +#define arch_atomic64_set generic_atomic64_set +#define arch_atomic64_set_release generic_atomic64_set + +#define arch_atomic64_add generic_atomic64_add +#define arch_atomic64_add_return generic_atomic64_add_return +#define arch_atomic64_fetch_add generic_atomic64_fetch_add +#define arch_atomic64_sub generic_atomic64_sub +#define arch_atomic64_sub_return generic_atomic64_sub_return +#define arch_atomic64_fetch_sub generic_atomic64_fetch_sub + +#define arch_atomic64_and generic_atomic64_and +#define arch_atomic64_fetch_and generic_atomic64_fetch_and +#define arch_atomic64_or generic_atomic64_or +#define arch_atomic64_fetch_or generic_atomic64_fetch_or +#define arch_atomic64_xor generic_atomic64_xor +#define arch_atomic64_fetch_xor generic_atomic64_fetch_xor + +#define arch_atomic64_dec_if_positive generic_atomic64_dec_if_positive +#define arch_atomic64_cmpxchg generic_atomic64_cmpxchg +#define arch_atomic64_xchg generic_atomic64_xchg +#define arch_atomic64_fetch_add_unless generic_atomic64_fetch_add_unless + +#endif /* _ASM_GENERIC_ATOMIC64_H */ -- cgit v1.3.1