From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752783AbaBGPUv (ORCPT ); Fri, 7 Feb 2014 10:20:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:64220 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751961AbaBGPUt (ORCPT ); Fri, 7 Feb 2014 10:20:49 -0500 From: Rafael Aquini To: linux-kernel@vger.kernel.org Cc: trond.myklebust@primarydata.com, jstancek@redhat.com, jlayton@redhat.com, mgorman@suse.de, riel@redhat.com, linux-nfs@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org Subject: [PATCH] mm: fix page leak at nfs_symlink() Date: Fri, 7 Feb 2014 13:19:54 -0200 Message-Id: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Changes committed by "a0b8cab3 mm: remove lru parameter from __pagevec_lru_add and remove parts of pagevec API" have introduced a call to add_to_page_cache_lru() which causes a leak in nfs_symlink() as now the page gets an extra refcount that is not dropped. Jan Stancek observed and reported the leak effect while running test8 from Connectathon Testsuite. After several iterations over the test case, which creates several symlinks on a NFS mountpoint, the test system was quickly getting into an out-of-memory scenario. This patch fixes the page leak by dropping that extra refcount add_to_page_cache_lru() is grabbing. Signed-off-by: Jan Stancek Signed-off-by: Rafael Aquini --- fs/nfs/dir.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index be38b57..4a48fe4 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1846,6 +1846,11 @@ int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) GFP_KERNEL)) { SetPageUptodate(page); unlock_page(page); + /* + * add_to_page_cache_lru() grabs an extra page refcount. + * Drop it here to avoid leaking this page later. + */ + page_cache_release(page); } else __free_page(page); -- 1.8.5.3