From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() 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 Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- Documentation/gpu/amdgpu/flashing.rst | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 Documentation/gpu/amdgpu/flashing.rst (limited to 'Documentation/gpu/amdgpu/flashing.rst') diff --git a/Documentation/gpu/amdgpu/flashing.rst b/Documentation/gpu/amdgpu/flashing.rst new file mode 100644 index 000000000..bd745c42a --- /dev/null +++ b/Documentation/gpu/amdgpu/flashing.rst @@ -0,0 +1,33 @@ +======================= + dGPU firmware flashing +======================= + +IFWI +---- +Flashing the dGPU integrated firmware image (IFWI) is supported by GPUs that +use the PSP to orchestrate the update (Navi3x or newer GPUs). +For supported GPUs, `amdgpu` will export a series of sysfs files that can be +used for the flash process. + +The IFWI flash process is: + +1. Ensure the IFWI image is intended for the dGPU on the system. +2. "Write" the IFWI image to the sysfs file `psp_vbflash`. This will stage the IFWI in memory. +3. "Read" from the `psp_vbflash` sysfs file to initiate the flash process. +4. Poll the `psp_vbflash_status` sysfs file to determine when the flash process completes. + +USB-C PD F/W +------------ +On GPUs that support flashing an updated USB-C PD firmware image, the process +is done using the `usbc_pd_fw` sysfs file. + +* Reading the file will provide the current firmware version. +* Writing the name of a firmware payload stored in `/lib/firmware/amdgpu` to the sysfs file will initiate the flash process. + +The firmware payload stored in `/lib/firmware/amdgpu` can be named any name +as long as it doesn't conflict with other existing binaries that are used by +`amdgpu`. + +sysfs files +----------- +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_psp.c -- cgit v1.3.1