vfs: fsmount: add missing mntget()
authorEric Biggers <ebiggers@google.com>
Wed, 12 Jun 2019 18:43:13 +0000 (11:43 -0700)
committerAl Viro <viro@zeniv.linux.org.uk>
Mon, 17 Jun 2019 21:36:07 +0000 (17:36 -0400)
commit1b0b9cc8d3793e31b313e6c9685513b08cd883c4
tree35a629a4bfb4025cf8a49335d5d3d39dd0187d01
parent9e0babf2c06c73cda2c0cd37a1653d823adb40ec
vfs: fsmount: add missing mntget()

sys_fsmount() needs to take a reference to the new mount when adding it
to the anonymous mount namespace.  Otherwise the filesystem can be
unmounted while it's still in use, as found by syzkaller.

Reported-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: syzbot+99de05d099a170867f22@syzkaller.appspotmail.com
Reported-by: syzbot+7008b8b8ba7df475fdc8@syzkaller.appspotmail.com
Fixes: 93766fbd2696 ("vfs: syscall: Add fsmount() to create a mount for a superblock")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/namespace.c