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/cmdline.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 tools/lib/cmdline.c (limited to 'tools/lib/cmdline.c') diff --git a/tools/lib/cmdline.c b/tools/lib/cmdline.c new file mode 100644 index 000000000..c85f00f43 --- /dev/null +++ b/tools/lib/cmdline.c @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * From lib/cmdline.c + */ +#include + +#if __has_attribute(__fallthrough__) +# define fallthrough __attribute__((__fallthrough__)) +#else +# define fallthrough do {} while (0) /* fallthrough */ +#endif + +unsigned long long memparse(const char *ptr, char **retptr) +{ + char *endptr; /* local pointer to end of parsed string */ + + unsigned long long ret = strtoll(ptr, &endptr, 0); + + switch (*endptr) { + case 'E': + case 'e': + ret <<= 10; + fallthrough; + case 'P': + case 'p': + ret <<= 10; + fallthrough; + case 'T': + case 't': + ret <<= 10; + fallthrough; + case 'G': + case 'g': + ret <<= 10; + fallthrough; + case 'M': + case 'm': + ret <<= 10; + fallthrough; + case 'K': + case 'k': + ret <<= 10; + endptr++; + fallthrough; + default: + break; + } + + if (retptr) + *retptr = endptr; + + return ret; +} -- cgit v1.3.1