drm/amdkfd: Destroy KFD debugfs after destroy KFD wq

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Destroy KFD debugfs after destroy KFD wq Since KFD proc content was moved to kernel debugfs, we can't destroy KFD debugfs before kfd_process_destroy_wq. Move kfd_process_destroy_wq prior to kfd_debugfs_fini to fix a kernel NULL pointer problem. It happens when /sys/kernel/debug/kfd was already destroyed in kfd_debugfs_fini but kfd_process_destroy_wq calls kfd_debugfs_remove_process. This line debugfs_remove_recursive(entry->proc_dentry); tries to remove /sys/kernel/debug/kfd/proc/<pid> while /sys/kernel/debug/kfd is already gone. It hangs the kernel by kernel NULL pointer. (cherry picked from commit 0333052d90683d88531558dcfdbf2525cc37c233)

References

• https://git.kernel.org/stable/c/fc35c955da799ba62f6f977d58e0866d0251e3f8
• https://git.kernel.org/stable/c/74ee7445c3b61c3bd899a54bd82c1982cb3a8206
• https://git.kernel.org/stable/c/96609a51e6134542bf90e053c2cd2fe4f61ebce3
• https://git.kernel.org/stable/c/910735ded17cc306625e7e1cdcc8102f7ac60994
• https://git.kernel.org/stable/c/2e58401a24e7b2d4ec619104e1a76590c1284a4c