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 --- scripts/extract-vmlinux | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100755 scripts/extract-vmlinux (limited to 'scripts/extract-vmlinux') diff --git a/scripts/extract-vmlinux b/scripts/extract-vmlinux new file mode 100755 index 000000000..266df9bc7 --- /dev/null +++ b/scripts/extract-vmlinux @@ -0,0 +1,65 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only +# ---------------------------------------------------------------------- +# extract-vmlinux - Extract uncompressed vmlinux from a kernel image +# +# Inspired from extract-ikconfig +# (c) 2009,2010 Dick Streefland +# +# (c) 2011 Corentin Chary +# +# ---------------------------------------------------------------------- + +me=${0##*/} + +check_vmlinux() +{ + if file "$1" | grep -q 'Linux kernel.*boot executable' || + readelf -h "$1" > /dev/null 2>&1 + then + cat "$1" + echo "$me: Extracted vmlinux using '$2' from offset $3" >&2 + exit 0 + fi +} + +try_decompress() +{ + # The obscure use of the "tr" filter is to work around older versions of + # "grep" that report the byte offset of the line instead of the pattern. + + # Try to find the header ($1) and decompress from here + for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"` + do + pos=${pos%%:*} + tail -c+$pos "$img" | $3 > $tmp 2> /dev/null + check_vmlinux $tmp "$3" $pos + done +} + +# Check invocation: +img=$1 +if [ $# -ne 1 -o ! -s "$img" ] +then + echo "Usage: $me " >&2 + exit 2 +fi + +# Prepare temp files: +tmp=$(mktemp /tmp/vmlinux-XXX) +trap "rm -f $tmp" 0 + +# That didn't work, so retry after decompression. +try_decompress '\037\213\010' xy gunzip +try_decompress '\3757zXZ\000' abcde unxz +try_decompress 'BZh' xy bunzip2 +try_decompress '\135\0\0\0' xxx unlzma +try_decompress '\211\114\132' xy 'lzop -d' +try_decompress '\002!L\030' xxx 'lz4 -d' +try_decompress '(\265/\375' xxx unzstd + +# Finally check for uncompressed images or objects: +check_vmlinux "$img" cat 0 + +# Bail out: +echo "$me: Cannot find vmlinux." >&2 -- cgit v1.3.1