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/stdlib.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 arch/powerpc/boot/stdlib.c (limited to 'arch/powerpc/boot/stdlib.c') diff --git a/arch/powerpc/boot/stdlib.c b/arch/powerpc/boot/stdlib.c new file mode 100644 index 000000000..868b019d6 --- /dev/null +++ b/arch/powerpc/boot/stdlib.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * stdlib functions + * + * Author: Scott Wood + * + * Copyright (c) 2007 Freescale Semiconductor, Inc. + */ + +#include "stdlib.h" + +/* Not currently supported: leading whitespace, sign, 0x prefix, zero base */ +unsigned long long int strtoull(const char *ptr, char **end, int base) +{ + unsigned long long ret = 0; + + if (base > 36) + goto out; + + while (*ptr) { + int digit; + + if (*ptr >= '0' && *ptr <= '9' && *ptr < '0' + base) + digit = *ptr - '0'; + else if (*ptr >= 'A' && *ptr < 'A' + base - 10) + digit = *ptr - 'A' + 10; + else if (*ptr >= 'a' && *ptr < 'a' + base - 10) + digit = *ptr - 'a' + 10; + else + break; + + ret *= base; + ret += digit; + ptr++; + } + +out: + if (end) + *end = (char *)ptr; + + return ret; +} -- cgit v1.3.1