ceph: fix error handling in ceph_read_iter

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 <kernel@kyup.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nikolay Borisov 2016-10-10 15:38:18 +03:00 committed by Greg Kroah-Hartman
parent 08cd19c602
commit e382e130d4

View file

@ -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;