diff mbox series

[1/1] sunrpc: cache_head leak due queued request

Message ID c103fa7e-419c-266a-45f3-7ee9ed8f5d10@virtuozzo.com (mailing list archive)
State New, archived
Headers show
Series [1/1] sunrpc: cache_head leak due queued request | expand

Commit Message

Vasily Averin Nov. 28, 2018, 8:45 a.m. UTC 
After commit d202cce8963d  expired cache_head can be removed from
hash on cache_detail.

However expired cache_head can wait for reply from previously submitted
request. Such cache_head have increased refcounter and therefore it
cannot be freed after cache_put(freeme).

Because cache_head was removed from hash it cannot be found during
cache_clean() and can be leaked forever together with stalled cache_request
and other taken resources.

Fixes d202cce8963d ("sunrpc: never return expired entries in sunrpc_cache_lookup")
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: stable@kernel.org # 2.6.35
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
 net/sunrpc/cache.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 109fbe591e7b..483a5cfd60f0 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -54,6 +54,11 @@  static void cache_init(struct cache_head *h, struct cache_detail *detail)
 	h->last_refresh = now;
 }
 
+static void cache_fresh_locked(struct cache_head *head, time_t expiry,
+			       struct cache_detail *detail);
+static void cache_fresh_unlocked(struct cache_head *head,
+				 struct cache_detail *detail);
+
 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
 				       struct cache_head *key, int hash)
 {
@@ -95,6 +100,7 @@  struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
 			if (cache_is_expired(detail, tmp)) {
 				hlist_del_init(&tmp->cache_list);
 				detail->entries --;
+				cache_fresh_locked(tmp, 0, detail);
 				freeme = tmp;
 				break;
 			}
@@ -110,8 +116,10 @@  struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
 	cache_get(new);
 	write_unlock(&detail->hash_lock);
 
-	if (freeme)
+	if (freeme) {
+		cache_fresh_unlocked(freeme, detail);
 		cache_put(freeme, detail);
+	}
 	return new;
 }
 EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);