tree 4f7d7c6bacdd04699ec030081195d84feacc0506
parent 8c9be1e58a8dc03ef815ca51ece95c5e6862b25e
author yangerkun <yangerkun@huawei.com> 1603864577 +0800
committer Theodore Ts'o <tytso@mit.edu> 1603906993 -0400

ext4: do not use extent after put_bh

ext4_ext_search_right() will read more extent blocks and call put_bh
after we get the information we need.  However, ret_ex will break this
and may cause use-after-free once pagecache has been freed.  Fix it by
copying the extent structure if needed.

Signed-off-by: yangerkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20201028055617.2569255-1-yangerkun@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org