4.8-stable review patch. If anyone has any objections, please let me know.
------------------ From: Nikolay Borisov <[email protected]> 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 <[email protected]> Reviewed-by: Yan, Zheng <[email protected]> Signed-off-by: Ilya Dryomov <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/ceph/file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -1272,7 +1272,8 @@ 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;
