From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932395AbcGLAWd (ORCPT ); Mon, 11 Jul 2016 20:22:33 -0400 Received: from p3plsmtpa11-06.prod.phx3.secureserver.net ([68.178.252.107]:37810 "EHLO p3plsmtpa11-06.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751698AbcGLAWb (ORCPT ); Mon, 11 Jul 2016 20:22:31 -0400 X-Greylist: delayed 432 seconds by postgrey-1.27 at vger.kernel.org; Mon, 11 Jul 2016 20:22:31 EDT From: Chunwei Chen To: linux-kernel@vger.kernel.org Cc: Chunwei Chen , Alexander Viro , linux-fsdevel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] vfs: check i_count under lock in evict_inodes Date: Mon, 11 Jul 2016 17:15:04 -0700 Message-Id: <1468282504-2272-1-git-send-email-david.chen@osnexus.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We need to check i_count again with i_lock held, because iput might re-add i_count when lazytime is on. Without this check, we could end up with double-free or use-after-free. Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Chunwei Chen --- fs/inode.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/inode.c b/fs/inode.c index 4ccbc21..10bb020 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -607,7 +607,12 @@ again: continue; spin_lock(&inode->i_lock); - if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { + /* + * check i_count again with lock, because iput might re-add + * it when lazytime is on. + */ + if (atomic_read(&inode->i_count) || + (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))) { spin_unlock(&inode->i_lock); continue; } -- 2.7.4