In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix AMDGPU_INFO_READ_MMR_REG
There were multiple issues in that code.
First of all the order between the reset semaphore and the mm_lock was wrong (e.g. copy_to_user) was called while holding the lock.
Then we allocated memory while holding the reset semaphore which is also a pretty big bug and can deadlock.
Then we used down_read_trylock() instead of waiting for the reset to finish.
(cherry picked from commit 361b6e6b303d4b691f6c5974d3eaab67ca6dd90e)
References
- https://git.kernel.org/stable/c/0ef196a208385b7d7da79f411c161b04e97283e2
- https://git.kernel.org/stable/c/5c29d20470d4566d1b68df57097d642d01f8b427
- https://git.kernel.org/stable/c/61957c2e467b39b528a290016367d32a433fa846
- https://git.kernel.org/stable/c/8c4254c8f5836e77ae83e7fc037f02b69f7a0977
- https://git.kernel.org/stable/c/a31c3feb54b15a90232e497ad0e27e8a82052d8d