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, 47 insertions, 0 deletions

diff --git a/net/ceph/Kconfig b/net/ceph/Kconfig
new file mode 100644
index 000000000..7e2528cde
--- /dev/null
+++ b/net/ceph/Kconfig
@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config CEPH_LIB
+	tristate "Ceph core library"
+	depends on INET
+	select CRC32
+	select CRYPTO_AES
+	select CRYPTO_CBC
+	select CRYPTO_GCM
+	select CRYPTO_KRB5
+	select CRYPTO_LIB_SHA256
+	select CRYPTO
+	select KEYS
+	default n
+	help
+	  Choose Y or M here to include cephlib, which provides the
+	  common functionality to both the Ceph filesystem and
+	  to the rados block device (rbd).
+
+	  More information at https://ceph.io/.
+
+	  If unsure, say N.
+
+config CEPH_LIB_PRETTYDEBUG
+	bool "Include file:line in ceph debug output"
+	depends on CEPH_LIB
+	default n
+	help
+	  If you say Y here, debug output will include a filename and
+	  line to aid debugging.  This increases kernel size and slows
+	  execution slightly when debug call sites are enabled (e.g.,
+	  via CONFIG_DYNAMIC_DEBUG).
+
+	  If unsure, say N.
+
+config CEPH_LIB_USE_DNS_RESOLVER
+	bool "Use in-kernel support for DNS lookup"
+	depends on CEPH_LIB
+	select DNS_RESOLVER
+	default n
+	help
+	  If you say Y here, hostnames (e.g. monitor addresses) will
+	  be resolved using the CONFIG_DNS_RESOLVER facility.
+
+	  For information on how to use CONFIG_DNS_RESOLVER consult
+	  Documentation/networking/dns_resolver.rst
+
+	  If unsure, say N.