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, 156 insertions, 0 deletions

diff --git a/Documentation/gpu/amdgpu/driver-misc.rst b/Documentation/gpu/amdgpu/driver-misc.rst
new file mode 100644
index 000000000..e1a964c3a
--- /dev/null
+++ b/Documentation/gpu/amdgpu/driver-misc.rst
@@ -0,0 +1,156 @@
+================================
+ Misc AMDGPU driver information
+================================
+
+GPU Product Information
+=======================
+
+Information about the GPU can be obtained on certain cards
+via sysfs
+
+product_name
+------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+   :doc: product_name
+
+product_number
+--------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+   :doc: product_number
+
+serial_number
+-------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+   :doc: serial_number
+
+fru_id
+-------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+   :doc: fru_id
+
+manufacturer
+-------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_fru_eeprom.c
+   :doc: manufacturer
+
+unique_id
+---------
+
+.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
+   :doc: unique_id
+
+board_info
+----------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+   :doc: board_info
+
+GPU Memory Usage Information
+============================
+
+Various memory accounting can be accessed via sysfs
+
+mem_info_vram_total
+-------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+   :doc: mem_info_vram_total
+
+mem_info_vram_used
+------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+   :doc: mem_info_vram_used
+
+mem_info_vis_vram_total
+-----------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+   :doc: mem_info_vis_vram_total
+
+mem_info_vis_vram_used
+----------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+   :doc: mem_info_vis_vram_used
+
+mem_info_gtt_total
+------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
+   :doc: mem_info_gtt_total
+
+mem_info_gtt_used
+-----------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
+   :doc: mem_info_gtt_used
+
+PCIe Accounting Information
+===========================
+
+pcie_bw
+-------
+
+.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
+   :doc: pcie_bw
+
+pcie_replay_count
+-----------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+   :doc: pcie_replay_count
+
+GPU SmartShift Information
+==========================
+
+GPU SmartShift information via sysfs
+
+smartshift_apu_power
+--------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
+   :doc: smartshift_apu_power
+
+smartshift_dgpu_power
+---------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
+   :doc: smartshift_dgpu_power
+
+smartshift_bias
+---------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
+   :doc: smartshift_bias
+
+UMA Carveout
+============
+
+Some versions of Atom ROM expose available options for the VRAM carveout sizes,
+and allow changes to the carveout size via the ATCS function code 0xA on supported
+BIOS implementations.
+
+For those platforms, users can use the following files under uma/ to set the
+carveout size, in a way similar to what Windows users can do in the "Tuning"
+tab in AMD Adrenalin.
+
+Note that for BIOS implementations that don't support this, these files will not
+be created at all.
+
+uma/carveout_options
+--------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+   :doc: uma/carveout_options
+
+uma/carveout
+--------------------
+
+.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+   :doc: uma/carveout