kernel/linux.git/drivers/media/platform/mediatek/vcodec, branch v6.18.35

media: mediatek: vcodec: fix use-after-free in encoder release path

2026-04-22T11:22:32+00:00

commit 76e35091ffc722ba39b303e48bc5d08abb59dd56 upstream. The fops_vcodec_release() function frees the context structure (ctx) without first cancelling any pending or running work in ctx->encode_work. This creates a race window where the workqueue handler (mtk_venc_worker) may still be accessing the context memory after it has been freed. Race condition: CPU 0 (release path) CPU 1 (workqueue) --------------------- ------------------ fops_vcodec_release() v4l2_m2m_ctx_release() v4l2_m2m_cancel_job() // waits for m2m job "done" mtk_venc_worker() v4l2_m2m_job_finish() // m2m job "done" // BUT worker still running! // post-job_finish access: other ctx dereferences // UAF if ctx already freed // returns (job "done") kfree(ctx) // ctx freed Root cause: The v4l2_m2m_ctx_release() only waits for the m2m job lifecycle (via TRANS_RUNNING flag), not the workqueue lifecycle. After v4l2_m2m_job_finish() is called, the m2m framework considers the job complete and v4l2_m2m_ctx_release() returns, but the worker function continues executing and may still access ctx. The work is queued during encode operations via: queue_work(ctx->dev->encode_workqueue, &ctx->encode_work) The worker function accesses ctx->m2m_ctx, ctx->dev, and other ctx fields even after calling v4l2_m2m_job_finish(). This vulnerability was confirmed with KASAN by running an instrumented test module that widens the post-job_finish race window. KASAN detected: BUG: KASAN: slab-use-after-free in mtk_venc_worker+0x159/0x180 Read of size 4 at addr ffff88800326e000 by task kworker/u8:0/12 Workqueue: mtk_vcodec_enc_wq mtk_venc_worker Allocated by task 47: __kasan_kmalloc+0x7f/0x90 fops_vcodec_open+0x85/0x1a0 Freed by task 47: __kasan_slab_free+0x43/0x70 kfree+0xee/0x3a0 fops_vcodec_release+0xb7/0x190 Fix this by calling cancel_work_sync(&ctx->encode_work) before kfree(ctx). This ensures the workqueue handler is both cancelled (if pending) and synchronized (waits for any running handler to complete) before the context is freed. Placement rationale: The fix is placed after v4l2_ctrl_handler_free() and before list_del_init(&ctx->list). At this point, all m2m operations are done (v4l2_m2m_ctx_release() has returned), and we need to ensure the workqueue is synchronized before removing ctx from the list and freeing it. Note: The open error path does NOT need cancel_work_sync() because INIT_WORK() only initializes the work structure - it does not schedule it. Work is only scheduled later during device_run() operations. Fixes: 0934d3759615 ("media: mediatek: vcodec: separate decoder and encoder") Cc: stable@vger.kernel.org Signed-off-by: Fan Wu Reviewed-by: Nicolas Dufresne Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil Signed-off-by: Greg Kroah-Hartman

media: mediatek: encoder: Fix uninitialized scalar variable issue

2026-03-04T12:20:56+00:00

[ Upstream commit 88e935de7cf8795d7a6a51385db87ecb361a7050 ] UNINIT checker finds some instances of variables that are used without being initialized, for example using the uninitialized value enc_result.is_key_frm can result in unpredictable behavior, so initialize these variables after declaring. Fixes: 4e855a6efa54 ("[media] vcodec: mediatek: Add Mediatek V4L2 Video Encoder Driver") Cc: stable@vger.kernel.org Signed-off-by: Irui Wang Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin

media: mediatek: vcodec: Don't try to decode 422/444 VP9

2026-03-04T12:19:52+00:00

[ Upstream commit 3e92d7e4935084ecdbdc88880cc4688618ae1557 ] This is not supported by the hardware and trying to decode these leads to LAT timeout errors. Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin

media: mediatek: vcodec: Fix a reference leak in mtk_vcodec_fw_vpu_init()

2026-01-08T09:17:05+00:00

commit cdd0f118ef87db8a664fb5ea366fd1766d2df1cd upstream. vpu_get_plat_device() increases the reference count of the returned platform device. However, when devm_kzalloc() fails, the reference is not released, causing a reference leak. Fix this by calling put_device() on fw_pdev->dev before returning on the error path. Fixes: e25a89f743b1 ("media: mtk-vcodec: potential dereference of null pointer") Cc: stable@vger.kernel.org Signed-off-by: Haoxiang Li Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: Tzung-Bi Shih Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil Signed-off-by: Greg Kroah-Hartman

media: mediatek: vcodec: Use spinlock for context list protection lock

2026-01-08T09:17:05+00:00

commit a5844227e0f030d2af2d85d4aed10c5eca6ca176 upstream. Previously a mutex was added to protect the encoder and decoder context lists from unexpected changes originating from the SCP IP block, causing the context pointer to go invalid, resulting in a NULL pointer dereference in the IPI handler. Turns out on the MT8173, the VPU IPI handler is called from hard IRQ context. This causes a big warning from the scheduler. This was first reported downstream on the ChromeOS kernels, but is also reproducible on mainline using Fluster with the FFmpeg v4l2m2m decoders. Even though the actual capture format is not supported, the affected code paths are triggered. Since this lock just protects the context list and operations on it are very fast, it should be OK to switch to a spinlock. Fixes: 6467cda18c9f ("media: mediatek: vcodec: adding lock to protect decoder context list") Fixes: afaaf3a0f647 ("media: mediatek: vcodec: adding lock to protect encoder context list") Cc: Yunfei Dong Cc: stable@vger.kernel.org Signed-off-by: Chen-Yu Tsai Reviewed-by: Fei Shao Reviewed-by: Tomasz Figa Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil Signed-off-by: Greg Kroah-Hartman

media: mtk: vcodec: Access v4l2_fh from file

2025-08-13T06:33:49+00:00

The v4l2_fh associated with an open file handle is now guaranteed to be available in file->private_data, initialised by v4l2_fh_add(). Access the v4l2_fh, and from there the driver-specific structure, from the file * in all ioctl handlers. While at modify mtk_vcodec_enc_get_chip_name() to accept a ctx instead of a raw void *. Signed-off-by: Jacopo Mondi Co-developed-by: Laurent Pinchart Signed-off-by: Laurent Pinchart Signed-off-by: Hans Verkuil

media: Reset file->private_data to NULL in v4l2_fh_del()

2025-08-13T06:33:44+00:00

Multiple drivers that use v4l2_fh and call v4l2_fh_del() manually reset the file->private_data pointer to NULL in their video device .release() file operation handler. Move the code to the v4l2_fh_del() function to avoid direct access to file->private_data in drivers. This requires adding a file pointer argument to the function. Changes to drivers have been generated with the following coccinelle semantic patch: @@ expression fh; identifier filp; identifier release; type ret; @@ ret release(..., struct file *filp, ...) { <... - filp->private_data = NULL; ... - v4l2_fh_del(fh); + v4l2_fh_del(fh, filp); ...> } @@ expression fh; identifier filp; identifier release; type ret; @@ ret release(..., struct file *filp, ...) { <... - v4l2_fh_del(fh); + v4l2_fh_del(fh, filp); ... - filp->private_data = NULL; ...> } @@ expression fh; identifier filp; identifier release; type ret; @@ ret release(..., struct file *filp, ...) { <... - v4l2_fh_del(fh); + v4l2_fh_del(fh, filp); ...> } Manual changes have been applied to Documentation/ to update the usage patterns, to drivers/media/v4l2-core/v4l2-fh.c to update the v4l2_fh_del() prototype and reset file->private_data, and to include/media/v4l2-fh.h to update the v4l2_fh_del() function prototype and its documentation. Additionally, white space issues have been fixed manually in drivers/usb/gadget/function/uvc_v4l2.c Signed-off-by: Laurent Pinchart Signed-off-by: Hans Verkuil

media: Set file->private_data in v4l2_fh_add()

2025-08-13T06:33:39+00:00

All the drivers that use v4l2_fh and call v4l2_fh_add() manually store a pointer to the v4l2_fh instance in file->private_data in their video device .open() file operation handler. Move the code to the v4l2_fh_add() function to avoid direct access to file->private_data in drivers. This requires adding a file pointer argument to the function. Changes to drivers have been generated with the following coccinelle semantic patch: @@ expression fh; identifier filp; identifier open; type ret; @@ ret open(..., struct file *filp, ...) { <... - filp->private_data = fh; ... - v4l2_fh_add(fh); + v4l2_fh_add(fh, filp); ...> } @@ expression fh; identifier filp; identifier open; type ret; @@ ret open(..., struct file *filp, ...) { <... - v4l2_fh_add(fh); + v4l2_fh_add(fh, filp); ... - filp->private_data = fh; ...> } Manual changes have been applied to Documentation/ to update the usage patterns, to drivers/media/v4l2-core/v4l2-fh.c to update the v4l2_fh_add() prototype set file->private_data, and to include/media/v4l2-fh.h to update the v4l2_fh_add() function prototype and its documentation. Additionally, white space issues have been fixed manually in drivers/media/platform/nvidia/tegra-vde/v4l2.c, drivers/media/platform/rockchip/rkvdec/rkvdec.c, drivers/media/v4l2-core/v4l2-fh.c and drivers/staging/most/video/video.c. Signed-off-by: Laurent Pinchart Signed-off-by: Hans Verkuil

media: Replace file->private_data access with custom functions

2025-08-13T06:33:30+00:00

Accessing file->private_data manually to retrieve the v4l2_fh pointer is error-prone, as the field is a void * and will happily cast implicitly to any pointer type. Replace all remaining locations that read the v4l2_fh pointer directly from file->private_data and cast it to driver-specific file handle structures with driver-specific functions that use file_to_v4l2_fh() and perform the same cast. No functional change is intended, this only paves the way to remove direct accesses to file->private_data and make V4L2 drivers safer. Other accesses to the field will be addressed separately. Signed-off-by: Laurent Pinchart Signed-off-by: Hans Verkuil

media: mediatek: vcodec: Enable HEVC main still picture decode

2025-04-24T13:21:34+00:00

Mediatek devices that support HEVC also support the main still picture profile, but today, the main still picture profile is excluded. This removes the skip mask for HEVC, and enables the main still picture profile decoding. Signed-off-by: Nathan Hebert Reviewed-by: Nicolas Dufresne Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil