4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown <neilb@xxxxxxxx> commit 9fa4eb8e490a28de40964b1b0e583d8db4c7e57c upstream. If a positive status is passed with the AUTOFS_DEV_IOCTL_FAIL ioctl, autofs4_d_automount() will return ERR_PTR(status) with that status to follow_automount(), which will then dereference an invalid pointer. So treat a positive status the same as zero, and map to ENOENT. See comment in systemd src/core/automount.c::automount_send_ready(). Link: http://lkml.kernel.org/r/871sqwczx5.fsf@xxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: NeilBrown <neilb@xxxxxxxx> Cc: Ian Kent <raven@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/autofs4/dev-ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/autofs4/dev-ioctl.c +++ b/fs/autofs4/dev-ioctl.c @@ -345,7 +345,7 @@ static int autofs_dev_ioctl_fail(struct int status; token = (autofs_wqt_t) param->fail.token; - status = param->fail.status ? param->fail.status : -ENOENT; + status = param->fail.status < 0 ? param->fail.status : -ENOENT; return autofs4_wait_release(sbi, token, status); }