Hello,
My static analysis tool reports a possible ABBA deadlock in the drm
driver in Linux 5.10:
drm_gem_prime_fd_to_handle()
mutex_lock(&dev->object_name_lock); --> Line 313 (Lock A)
drm_gem_handle_delete()
drm_gem_object_release_handle()
drm_gem_remove_prime_handles()
mutex_lock(&filp->prime.lock); --> Line 16 (Lock B)
drm_gem_prime_handle_to_fd()
mutex_lock(&file_priv->prime.lock); --> Line 433 (Lock B)
mutex_lock(&dev->object_name_lock); --> Line 466 (Lock A)
When drm_gem_prime_fd_to_handle() and drm_gem_prime_handle_to_fd() are
concurrently executed, the deadlock can occur.
I am not quite sure whether this possible deadlock is real and how to
fix it if it is real.
Any feedback would be appreciated, thanks :)
Reported-by: TOTE Robot <[email protected]>
Best wishes,
Jia-Ju Bai