kernel: ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock

In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Fix potential AB/BA lock with buffermutex and mmaplock syzbot caught a potential deadlock between the PCM runtime-buffermutex and the mm-mmaplock. It was brought by the recent fix to cover the racy read/write and other...