* [PATCH] locking/lockdep: Prevent abuse of lockdep subclass
@ 2025-04-09 14:37 Waiman Long
2025-05-04 18:03 ` Boqun Feng
0 siblings, 1 reply; 2+ messages in thread
From: Waiman Long @ 2025-04-09 14:37 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Will Deacon, Boqun Feng
Cc: linux-kernel, Waiman Long
As I have seen 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.
Signed-off-by: Waiman Long <longman@redhat.com>
---
kernel/locking/lockdep.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 58d78a33ac65..3fb79d8fecdf 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -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];
/*
--
2.48.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] locking/lockdep: Prevent abuse of lockdep subclass
2025-04-09 14:37 [PATCH] locking/lockdep: Prevent abuse of lockdep subclass Waiman Long
@ 2025-05-04 18:03 ` Boqun Feng
0 siblings, 0 replies; 2+ messages in thread
From: Boqun Feng @ 2025-05-04 18:03 UTC (permalink / raw)
To: Waiman Long; +Cc: Peter Zijlstra, Ingo Molnar, Will Deacon, linux-kernel
On Wed, Apr 09, 2025 at 10:37:51AM -0400, Waiman Long wrote:
> As I have seen 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.
>
> Signed-off-by: Waiman Long <longman@redhat.com>
Queued for 6.16, thanks!
Regards,
Boqun
> ---
> kernel/locking/lockdep.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index 58d78a33ac65..3fb79d8fecdf 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -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];
> /*
> --
> 2.48.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2025-05-04 18:03 ` Boqun Feng
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