Commit 179ccc0a authored Dec 19, 2015 by Herbert Xu Committed by David S. Miller Dec 18, 2015

rhashtable: Kill harmless RCU warning in rhashtable_walk_init



The commit c6ff5268 ("rhashtable:
Fix walker list corruption") causes a suspicious RCU usage warning
because we no longer hold ht->mutex when we dereference ht->tbl.

However, this is a false positive because we now hold ht->lock
which also guarantees that ht->tbl won't disppear from under us.

This patch kills the warning by using rcu_dereference_protected.

Reported-by: kernel test robot <ying.huang@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent e905eabc

lib/rhashtable.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -519,7 +519,8 @@ int rhashtable_walk_init(struct rhashtable ht, struct rhashtable_iter iter)
		return -ENOMEM;

		spin_lock(&ht->lock);
		iter->walker->tbl = rht_dereference(ht->tbl, ht);
		iter->walker->tbl =
		rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock));
		list_add(&iter->walker->list, &iter->walker->tbl->walkers);
		spin_unlock(&ht->lock);