From 179ccc0a73641ffd24e44ff10a7bd494efe98d8d Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sat, 19 Dec 2015 10:45:28 +0800 Subject: [PATCH] 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 --- lib/rhashtable.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) 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); -- 2.20.1