>> But doesn't it race even with regular PF handling, not only the fork? How >> do we handle this race? > > With the regular #PF handing, the faulting thread patiently waits until > page fault is resolved. With fork(), mremap() etc the thread that caused > the event resumes once the uffd message is read by the monitor. That's > surely way before monitor had chance to somehow process that message. Ouch, yes. This is nasty :( So having no better solution in mind, let's move forward with this. Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
