From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3290BC10F0C for ; Tue, 2 Apr 2019 13:40:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 09F902070B for ; Tue, 2 Apr 2019 13:40:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731574AbfDBNkP (ORCPT ); Tue, 2 Apr 2019 09:40:15 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42850 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731173AbfDBNkC (ORCPT ); Tue, 2 Apr 2019 09:40:02 -0400 Received: from [167.98.27.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hBJdv-0002n8-AM; Tue, 02 Apr 2019 14:39:59 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hBJdu-0004sC-9a; Tue, 02 Apr 2019 14:39:58 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "NeilBrown" , "J. Bruce Fields" , "Pavel Tikhomirov" , "Vasily Averin" Date: Tue, 02 Apr 2019 14:38:27 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 22/99] sunrpc: fix cache_head leak due to queued request In-Reply-To: X-SA-Exim-Connect-IP: 167.98.27.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.65-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Vasily Averin 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 Signed-off-by: Vasily Averin Reviewed-by: NeilBrown Signed-off-by: J. Bruce Fields [bwh: Backported to 3.16: - cache_fresh_lock() doesn't take a struct cache_detail pointer - Adjust context] Signed-off-by: Ben Hutchings --- net/sunrpc/cache.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -50,6 +50,10 @@ static void cache_init(struct cache_head h->last_refresh = now; } +static void cache_fresh_locked(struct cache_head *head, time_t expiry); +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) { @@ -94,6 +98,7 @@ struct cache_head *sunrpc_cache_lookup(s *hp = tmp->next; tmp->next = NULL; detail->entries --; + cache_fresh_locked(tmp, 0); freeme = tmp; break; } @@ -109,8 +114,10 @@ struct cache_head *sunrpc_cache_lookup(s 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);