fscrypt: fix keyring memory leak on mount failure

stable inclusion
from stable-v5.10.154
commit 29997a6fa60de1de2fa0de471e7652efa6e95868
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=29997a6fa60de1de2fa0de471e7652efa6e95868



--------------------------------

commit ccd30a47 upstream.

Commit d7e7b9af ("fscrypt: stop using keyrings subsystem for
fscrypt_master_key") moved the keyring destruction from __put_super() to
generic_shutdown_super() so that the filesystem's block device(s) are
still available.  Unfortunately, this causes a memory leak in the case
where a mount is attempted with the test_dummy_encryption mount option,
but the mount fails after the option has already been processed.

To fix this, attempt the keyring destruction in both places.

Reported-by:  <syzbot+104c2a89561289cec13e@syzkaller.appspotmail.com>
Fixes: d7e7b9af ("fscrypt: stop using keyrings subsystem for fscrypt_master_key")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20221011213838.209879-1-ebiggers@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lipeng Sang <sanglipeng1@jd.com>

Conflicts:
	fs/super.c