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| author | Vasily Averin <vvs@virtuozzo.com> | 2018-11-28 11:45:57 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-13 12:03:51 +0300 |
| commit | 9369b7dd1019a5904978227e51cd4c78b01a92c8 (patch) | |
| tree | e822b386f9f37397f011770abd165bdd88f46db2 /net/sunrpc | |
| parent | 298cf9b3308cfc6f3ab6c7a29b2d3df9e85cfe91 (diff) | |
| download | linux-9369b7dd1019a5904978227e51cd4c78b01a92c8.tar.xz | |
sunrpc: fix cache_head leak due to queued request
commit 4ecd55ea074217473f94cfee21bb72864d39f8d7 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/sunrpc')
| -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 8aabe12201f8..cab50ece6f3d 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); |