Re: [PATCH 3/9] x86/entry/32: fix the end of the stack for newly forked tasks

From: Josh Poimboeuf
Date: Wed Sep 21 2016 - 07:35:31 EST


On Tue, Sep 20, 2016 at 11:39:35PM -0700, Andy Lutomirski wrote:
> > And the ia64 entry code has some similar language:
> >
> > /*
> > * Invoke schedule_tail(task) while preserving in0-in7, which may be needed
> > * in case a system call gets restarted.
> > */
> > GLOBAL_ENTRY(ia64_invoke_schedule_tail)
> > ...
>
> That comment has to be wrong. What syscall could possibly be
> restarted across schedule_tail()? It's a brand new thread and has
> literally never done a syscall.

Hm, yeah, that comment doesn't make any sense.

> There may be another reason that the registers are live there, but I
> generally do my best to never look at ia64 asm code.

Yeah, I'm just going to turn around, pretend I never saw it, and slowly
walk away...

--
Josh