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/gdb/vmlinux-gdb.py | 52 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 scripts/gdb/vmlinux-gdb.py (limited to 'scripts/gdb/vmlinux-gdb.py') diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py new file mode 100644 index 000000000..d4eeed450 --- /dev/null +++ b/scripts/gdb/vmlinux-gdb.py @@ -0,0 +1,52 @@ +# +# gdb helper commands and functions for Linux kernel debugging +# +# loader module +# +# Copyright (c) Siemens AG, 2012, 2013 +# +# Authors: +# Jan Kiszka +# +# This work is licensed under the terms of the GNU GPL version 2. +# + +import os + +sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)) + "/scripts/gdb") + +try: + gdb.parse_and_eval("0") + gdb.execute("", to_string=True) +except: + gdb.write("NOTE: gdb 7.2 or later required for Linux helper scripts to " + "work.\n") +else: + import linux.constants + if linux.constants.LX_CONFIG_DEBUG_INFO_REDUCED: + raise gdb.GdbError("Reduced debug information will prevent GDB " + "from having complete types.\n") + import linux.utils + import linux.symbols + import linux.modules + import linux.dmesg + import linux.tasks + import linux.config + import linux.cpus + import linux.lists + import linux.rbtree + import linux.proc + import linux.timerlist + import linux.clk + import linux.genpd + import linux.device + import linux.vfs + import linux.pgtable + import linux.radixtree + import linux.interrupts + import linux.mm + import linux.stackdepot + import linux.page_owner + import linux.slab + import linux.vmalloc + import linux.kasan -- cgit v1.3.1