Theodore Y. Ts'o wrote: > On Mon, May 07, 2018 at 10:21:04PM +0900, Tetsuo Handa wrote: > > > I don't understand your concern; where are we going to out_putf when > > > error == 0? > > Ah, now I see it, thanks. I'll send a revised patch. > > > By the way, are you aware that current "/* Avoid recursion */" loop is not thread safe? > > Actually, it is safe. While the child loop device has an open file on > the parent, lo_refcnt is elevated, which prevents loop_clr_fd from > actually set setting lo_state to Lo_rundown and clearing > lo_backing_file If you think it is safe, please explain that the crash referenced in a patch at https://groups.google.com/d/msg/syzkaller-bugs/2Rw8-OM6IbM/PzdobV8kAgAJ is no longer possible. syzbot is hitting crashes there.