commit 3510c7aa069aa83a2de6dab2b41401a198317bdc
author Takashi Iwai <tiwai@suse.de> Mon Nov 06 20:16:50 2017 +0100
committer Takashi Iwai <tiwai@suse.de> Mon Nov 06 20:25:31 2017 +0100
tree 8af28de7f1a3247856d683267685ab96d5290983
parent 9b7d869ee5a77ed4a462372bb89af622e705bfb8

ALSA: seq: Avoid invalid lockdep class warning

The recent fix for adding rwsem nesting annotation was using the given
"hop" argument as the lock subclass key.  Although the idea itself
works, it may trigger a kernel warning like:
  BUG: looking up invalid subclass: 8
  ....
since the lockdep has a smaller number of subclasses (8) than we
currently allow for the hops there (10).

The current definition is merely a sanity check for avoiding the too
deep delivery paths, and the 8 hops are already enough.  So, as a
quick fix, just follow the max hops as same as the max lockdep
subclasses.

Fixes: 1f20f9ff57ca ("ALSA: seq: Fix nested rwsem annotation for lockdep splat")
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>