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, 88 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/fuse/nvidia,tegra20-fuse.yaml b/Documentation/devicetree/bindings/fuse/nvidia,tegra20-fuse.yaml
new file mode 100644
index 000000000..02f0b0462
--- /dev/null
+++ b/Documentation/devicetree/bindings/fuse/nvidia,tegra20-fuse.yaml
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/fuse/nvidia,tegra20-fuse.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra FUSE block
+
+maintainers:
+  - Thierry Reding <thierry.reding@gmail.com>
+  - Jon Hunter <jonathanh@nvidia.com>
+
+properties:
+  compatible:
+    oneOf:
+      - enum:
+          - nvidia,tegra20-efuse
+          - nvidia,tegra30-efuse
+          - nvidia,tegra114-efuse
+          - nvidia,tegra124-efuse
+          - nvidia,tegra210-efuse
+          - nvidia,tegra186-efuse
+          - nvidia,tegra194-efuse
+          - nvidia,tegra234-efuse
+
+      - items:
+          - const: nvidia,tegra132-efuse
+          - const: nvidia,tegra124-efuse
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: fuse
+
+  resets:
+    maxItems: 1
+
+  reset-names:
+    items:
+      - const: fuse
+
+  operating-points-v2: true
+
+  power-domains:
+    items:
+      - description: phandle to the core power domain
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - nvidia,tegra20-efuse
+          - nvidia,tegra30-efuse
+          - nvidia,tegra114-efuse
+          - nvidia,tegra124-efuse
+          - nvidia,tegra132-efuse
+          - nvidia,tegra210-efuse
+then:
+  required:
+    - resets
+    - reset-names
+
+examples:
+  - |
+    #include <dt-bindings/clock/tegra20-car.h>
+
+    fuse@7000f800 {
+        compatible = "nvidia,tegra20-efuse";
+        reg = <0x7000f800 0x400>;
+        clocks = <&tegra_car TEGRA20_CLK_FUSE>;
+        clock-names = "fuse";
+        resets = <&tegra_car 39>;
+        reset-names = "fuse";
+    };