From 3510c7aa069aa83a2de6dab2b41401a198317bdc Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 6 Nov 2017 20:16:50 +0100 Subject: [PATCH] ALSA: seq: Avoid invalid lockdep class warning Git-commit: 3510c7aa069aa83a2de6dab2b41401a198317bdc Patch-mainline: v4.14 References: bsc#1051510 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 Cc: Signed-off-by: Takashi Iwai --- include/sound/seq_kernel.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/sound/seq_kernel.h b/include/sound/seq_kernel.h index feb58d455560..4b9ee3009aa0 100644 --- a/include/sound/seq_kernel.h +++ b/include/sound/seq_kernel.h @@ -49,7 +49,8 @@ typedef union snd_seq_timestamp snd_seq_timestamp_t; #define SNDRV_SEQ_DEFAULT_CLIENT_EVENTS 200 /* max delivery path length */ -#define SNDRV_SEQ_MAX_HOPS 10 +/* NOTE: this shouldn't be greater than MAX_LOCKDEP_SUBCLASSES */ +#define SNDRV_SEQ_MAX_HOPS 8 /* max size of event size */ #define SNDRV_SEQ_MAX_EVENT_LEN 0x3fffffff -- 2.15.1