dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()grafted

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 <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/tools/docs/check-variable-fonts.py b/tools/docs/check-variable-fonts.py
new file mode 100755
index 000000000..958d5a745
--- /dev/null
+++ b/tools/docs/check-variable-fonts.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) Akira Yokosawa, 2024
+#
+# Ported to Python by (c) Mauro Carvalho Chehab, 2025
+#
+# pylint: disable=C0103
+
+"""
+Detect problematic Noto CJK variable fonts.
+
+or more details, see .../tools/lib/python/kdoc/latex_fonts.py.
+"""
+
+import argparse
+import sys
+import os.path
+
+src_dir = os.path.dirname(os.path.realpath(__file__))
+sys.path.insert(0, os.path.join(src_dir, '../lib/python'))
+
+from kdoc.latex_fonts import LatexFontChecker
+
+checker = LatexFontChecker()
+
+parser=argparse.ArgumentParser(description=checker.description(),
+                               formatter_class=argparse.RawTextHelpFormatter)
+parser.add_argument("--deny-vf",
+                    help="XDG_CONFIG_HOME dir containing fontconfig/fonts.conf file")
+
+args=parser.parse_args()
+
+msg = LatexFontChecker(args.deny_vf).check()
+if msg:
+    print(msg)
+
+sys.exit(1)