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| author | Vasily Averin <vvs@virtuozzo.com> | 2018-11-28 11:45:57 +0300 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2018-12-04 15:42:08 -0500 |
| commit | 4ecd55ea074217473f94cfee21bb72864d39f8d7 (patch) | |
| tree | 273aa85947dace0ad1f2a7d6dd2350e07a658719 | |
| parent | f50c9d797d3df41e13265491c722d3d15b038d57 (diff) | |
| download | linux-stable-4ecd55ea074217473f94cfee21bb72864d39f8d7.tar.gz linux-stable-4ecd55ea074217473f94cfee21bb72864d39f8d7.tar.bz2 linux-stable-4ecd55ea074217473f94cfee21bb72864d39f8d7.zip | |
sunrpc: fix cache_head leak due to queued request
After commit d202cce8963d, an expired cache_head can be removed from the
cache_detail's hash.
However, the expired cache_head may be waiting for a reply from a
previously submitted request. Such a cache_head has an increased
refcounter and therefore it won't be freed after cache_put(freeme).
Because the cache_head was removed from the hash it cannot be found
during cache_clean() and can be leaked forever, together with stalled
cache_request and other taken resources.
In our case we noticed it because an entry in the export cache was
holding a reference on a filesystem.
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>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| -rw-r--r-- | net/sunrpc/cache.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index f96345b1180e..12bb23b8e0c5 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); + static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail, struct cache_head *key, int hash) @@ -100,6 +105,7 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail, if (cache_is_expired(detail, tmp)) { hlist_del_init_rcu(&tmp->cache_list); detail->entries --; + cache_fresh_locked(tmp, 0, detail); freeme = tmp; break; } @@ -115,8 +121,10 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail, cache_get(new); spin_unlock(&detail->hash_lock); - if (freeme) + if (freeme) { + cache_fresh_unlocked(freeme, detail); cache_put(freeme, detail); + } return new; } |