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, 39 insertions, 0 deletions

diff --git a/drivers/interconnect/Kconfig b/drivers/interconnect/Kconfig
new file mode 100644
index 000000000..882dcb0b4
--- /dev/null
+++ b/drivers/interconnect/Kconfig
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig INTERCONNECT
+	bool "On-Chip Interconnect management support"
+	help
+	  Support for management of the on-chip interconnects.
+
+	  This framework is designed to provide a generic interface for
+	  managing the interconnects in a SoC.
+
+	  If unsure, say no.
+
+if INTERCONNECT
+
+source "drivers/interconnect/imx/Kconfig"
+source "drivers/interconnect/mediatek/Kconfig"
+source "drivers/interconnect/qcom/Kconfig"
+source "drivers/interconnect/samsung/Kconfig"
+
+config INTERCONNECT_CLK
+	tristate
+	depends on COMMON_CLK
+	help
+	  Support for wrapping clocks into the interconnect nodes.
+
+config INTERCONNECT_KUNIT_TEST
+	tristate "KUnit tests for Interconnect framework"
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit test suite for the generic system interconnect
+	  framework.
+
+	  The tests cover the core functionality of the interconnect subsystem,
+	  including provider/consumer APIs, topology management, and bandwidth
+	  aggregation logic.
+
+	  If unsure, say N.
+
+endif