drm/msm/mdp5: Return error code in mdp5_pipe_release when deadlock is detected

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/msm/mdp5: Return error code in mdp5_pipe_release when deadlock is detected mdp5_get_global_state runs the risk of hitting a -EDEADLK when acquiring the modeset lock, but currently mdp5_pipe_release doesn't check for if an error is returned. Because of this, there is a possibility of mdp5_pipe_release hitting a NULL dereference error. To avoid this, let's have mdp5_pipe_release check if mdp5_get_global_state returns an error and propogate that error. Changes since v1: - Separated declaration and initialization of *new_state to avoid compiler warning - Fixed some spelling mistakes in commit message Changes since v2: - Return 0 in case where hwpipe is NULL as this is considered normal behavior - Added 2nd patch in series to fix a similar NULL dereference issue in mdp5_mixer_release Patchwork: https://patchwork.freedesktop.org/patch/485179/

References

• https://git.kernel.org/stable/c/776f5c58bfe16cf322d71eeed3c5dda1eeac7e6b
• https://git.kernel.org/stable/c/b2aa2c4efe93e2580d6a8774b04fe2b99756a322
• https://git.kernel.org/stable/c/49dc28b4b2e28ef7564e355c91487996c1cbebd7
• https://git.kernel.org/stable/c/04bef5f1ba8ea6d7c1c8f5f65e0395c62db59cb8
• https://git.kernel.org/stable/c/19964dfb39bda4d7716a71009488f0668ecbcf52
• https://git.kernel.org/stable/c/33dc5aac46e0fad8f5eb193e5906ed0eb6b66ceb
• https://git.kernel.org/stable/c/d59be579fa932c46b908f37509f319cbd4ca9a68