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authorHerbert Xu <herbert@gondor.apana.org.au>2015-12-16 16:45:54 +0800
committerDavid S. Miller <davem@davemloft.net>2015-12-16 11:13:14 -0500
commitc6ff5268293ef98e48a99597e765ffc417e39fa5 (patch)
tree383abd638c072a92aab2e874870607b1147b8797 /lib
parent3a324606bbabfc30084ce9d08169910773ba9a92 (diff)
downloadleg-kernel-c6ff5268293ef98e48a99597e765ffc417e39fa5.tar.gz
rhashtable: Fix walker list corruption
The commit ba7c95ea3870fe7b847466d39a049ab6f156aa2c ("rhashtable: Fix sleeping inside RCU critical section in walk_stop") introduced a new spinlock for the walker list. However, it did not convert all existing users of the list over to the new spin lock. Some continued to use the old mutext for this purpose. This obviously led to corruption of the list. The fix is to use the spin lock everywhere where we touch the list. This also allows us to do rcu_rad_lock before we take the lock in rhashtable_walk_start. With the old mutex this would've deadlocked but it's safe with the new spin lock. Fixes: ba7c95ea3870 ("rhashtable: Fix sleeping inside RCU...") Reported-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib')
-rw-r--r--lib/rhashtable.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index a98e71db7dd2..eb9240c458fa 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -518,10 +518,10 @@ int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter)
if (!iter->walker)
return -ENOMEM;
- mutex_lock(&ht->mutex);
+ spin_lock(&ht->lock);
iter->walker->tbl = rht_dereference(ht->tbl, ht);
list_add(&iter->walker->list, &iter->walker->tbl->walkers);
- mutex_unlock(&ht->mutex);
+ spin_unlock(&ht->lock);
return 0;
}
@@ -535,10 +535,10 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_init);
*/
void rhashtable_walk_exit(struct rhashtable_iter *iter)
{
- mutex_lock(&iter->ht->mutex);
+ spin_lock(&iter->ht->lock);
if (iter->walker->tbl)
list_del(&iter->walker->list);
- mutex_unlock(&iter->ht->mutex);
+ spin_unlock(&iter->ht->lock);
kfree(iter->walker);
}
EXPORT_SYMBOL_GPL(rhashtable_walk_exit);
@@ -562,14 +562,12 @@ int rhashtable_walk_start(struct rhashtable_iter *iter)
{
struct rhashtable *ht = iter->ht;
- mutex_lock(&ht->mutex);
+ rcu_read_lock();
+ spin_lock(&ht->lock);
if (iter->walker->tbl)
list_del(&iter->walker->list);
-
- rcu_read_lock();
-
- mutex_unlock(&ht->mutex);
+ spin_unlock(&ht->lock);
if (!iter->walker->tbl) {
iter->walker->tbl = rht_dereference_rcu(ht->tbl, ht);