Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752511AbcJJM4t (ORCPT ); Mon, 10 Oct 2016 08:56:49 -0400 Received: from mail-qk0-f177.google.com ([209.85.220.177]:35506 "EHLO mail-qk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752159AbcJJM4r (ORCPT ); Mon, 10 Oct 2016 08:56:47 -0400 From: Nikolay Borisov To: zyan@redhat.com, idryomov@gmail.com Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Nikolay Borisov Subject: [PATCHv2] ceph: Fix error handling in ceph_read_iter Date: Mon, 10 Oct 2016 15:56:39 +0300 Message-Id: <1476104199-3259-1-git-send-email-kernel@kyup.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1476103098-2925-1-git-send-email-kernel@kyup.com> References: <1476103098-2925-1-git-send-email-kernel@kyup.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1033 Lines: 34 In case __ceph_do_getattr returns an error and the retry_op in ceph_read_iter is not READ_INLINE, then it's possible to invoke __free_page on a page which is NULL, this naturally leads to a crash. This can happen when, for example, a process waiting on a MDS reply receives sigterm. Fix this by explicitly checking whether the page is set or not. Signed-off-by: Nikolay Borisov Link: http://www.spinics.net/lists/ceph-users/msg31592.html --- Inverted the condition, so resending with correct condition this time. fs/ceph/file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ceph/file.c b/fs/ceph/file.c index 3c68e6aee2f0..7413313ae6c8 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -929,7 +929,8 @@ again: statret = __ceph_do_getattr(inode, page, CEPH_STAT_CAP_INLINE_DATA, !!page); if (statret < 0) { - __free_page(page); + if (page) + __free_page(page); if (statret == -ENODATA) { BUG_ON(retry_op != READ_INLINE); goto again; -- 2.5.0