CVE-2026-89885media: platform: mtk-mdp3: Fix SCP device refcounting

Official description

In the Linux kernel, the following vulnerability has been resolved: media: platform: mtk-mdp3: Fix SCP device refcounting mdp_probe() first tries to get the SCP handle with scp_get(). When that fails, it falls back to looking up the SCP platform device with __get_pdev_by_id() and then reads its driver data. The fallback lookup returns the platform device with a reference, just like scp_get() does. However, the fallback path currently drops that reference immediately after platform_get_drvdata(). The driver later still calls scp_put(mdp->scp) unconditionally from the probe error path and from mdp_video_device_release(), which drops the SCP device reference again. Keep the fallback reference until the existing scp_put() call, so that the fallback path follows the same ownership rules as the scp_get() path.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/dce13bd9bade3ecc1acb7579397f24743850997f
• https://git.kernel.org/stable/c/252850653569fdb1a259937e02325cf32c8f0970
• https://git.kernel.org/stable/c/0259ade4c4ceaf1e184a7c1aea8071ad398f9b6f
• https://git.kernel.org/stable/c/55793e4665b7f15151e6f5ab51ca980e73abed5d