ceph: fix error handling in ceph_read_iter
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.
Cc: stable@vger.kernel.org # 3.19+
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 7bf0882..18630e8 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1272,7 +1272,8 @@
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;