[Linux-cachefs] [PATCH] Use proper lock in fscache_objlist_config.

David Howells dhowells at redhat.com
Tue Oct 4 15:43:31 UTC 2016


Artem Savkov <asavkov at redhat.com> wrote:

> fscache_objlist_config doesn't hold rkey->sem when calling user_key_payload,
> that can result in a "suspicious RCU usage" warning. It does hold
> rcu_read_lock,  so it either needs to use unprotected rcu_dereference,
> or take rkey->sem instead of rcu_read_lock.

It shouldn't take key->sem.  The RCU lock should be necessary as
user_key_payload() wraps a call to rcu_dereference().

Did you encounter a lockdep report or did you visually inspect this?

David




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