Commit 6a1a219f authored by Waiman Long's avatar Waiman Long Committed by Ingo Molnar
Browse files

locking/lockdep: Prevent abuse of lockdep subclass 



To catch the code trying to use a subclass value >= MAX_LOCKDEP_SUBCLASSES (8),
add a DEBUG_LOCKS_WARN_ON() statement to notify the users that such a
large value is not allowed.

[ boqun: Reword the commit log with a more objective tone ]

Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20250506042049.50060-3-boqun.feng@gmail.com
parent 96ca1830

kernel/locking/lockdep.c

+3 −0
Original line number Diff line number Diff line
@@ -5101,6 +5101,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
		lockevent_inc(lockdep_nocheck);

	}



	if (DEBUG_LOCKS_WARN_ON(subclass >= MAX_LOCKDEP_SUBCLASSES))

		return 0;



	if (subclass < NR_LOCKDEP_CACHING_CLASSES)

		class = lock->class_cache[subclass];

	/*