Re: Issues with "x86, um: switch to generic fork/vfork/clone" commit

From: Linus Torvalds
Date: Sun Jan 20 2013 - 15:53:26 EST


On Sat, Jan 19, 2013 at 7:12 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> OK... I think I understand what's going on. We need asmlinkage_protect
> in sys_clone() ;-/ For what it's worth, I really wonder if we ought to
> treat that as syscall wrappers - i.e. have SYSCALL_DEFINEx on i386 add
> a wrapper that would do asmlinkage_protect itself. IMO it's the same kind
> of thing as argument normalization handled by syscall wrappers - we make
> sure that C function plays well with what asm glue is doing and expecting.

Actually, I think we should do it *unconditionally* in the syscall wrappers.

It's up to the architecture code to make asmlinkage_protect() be a
no-op or not, depending on how it does things. Right now I think only
x86 actually defines it, although I suspect there might be others that
should (anybody who passes arguments on the stack and also uses the
stack for save-area).

But in the meantime, I guess I should just take the do_fork() one. Can
I get a sign-off and a changelog?

Linus
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