From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nikolay Borisov , "Yan, Zheng" , Ilya Dryomov Subject: [PATCH 4.4 101/112] ceph: fix error handling in ceph_read_iter Date: Wed, 26 Oct 2016 14:23:24 +0200 Message-Id: <20161026122309.044830972@linuxfoundation.org> In-Reply-To: <20161026122304.797016625@linuxfoundation.org> References: <20161026122304.797016625@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nikolay Borisov commit 0d7718f666be181fda1ba2d08f137d87c1419347 upstream. 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 Reviewed-by: Yan, Zheng Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman --- fs/ceph/file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- 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;