From: Herbert Xu Date: Sat, 19 Dec 2015 02:45:28 +0000 (+0800) Subject: rhashtable: Kill harmless RCU warning in rhashtable_walk_init X-Git-Tag: v4.4-rc8~5^2~20 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=179ccc0a73641ffd24e44ff10a7bd494efe98d8d;p=karo-tx-linux.git rhashtable: Kill harmless RCU warning in rhashtable_walk_init The commit c6ff5268293ef98e48a99597e765ffc417e39fa5 ("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 Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- diff --git a/lib/rhashtable.c b/lib/rhashtable.c index eb9240c458fa..51282f579760 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -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);