[alsa-devel] [BUG] ALSA: core: seq: a possible double-lock bug in snd_seq_midisynth_remove()

In snd_seq_midisynth_remove(), there is a possible double-lock bug: snd_seq_midisynth_remove()     mutex_lock(&register_mutex); -- line 421     snd_seq_delete_kernel_client() --- line 436         seq_free_client() -- line 2244             mutex_lock(&register_mutex); -- line 294

This bug is found by a static analysis tool STCheck written by us.

I do not know how to correctly fix this bug, so I only report it. A possible fix is to release the mutex lock before calling seq_free_client() in snd_seq_delete_kernel_client() and then acquiring the lock again after calling seq_free_client().

Best wishes, Jia-Ju Bai