Re: SYSCALL, ptrace and syscall restart breakages (Re: [RFC] weird crap with vdso on uml/i386)

Al Viro
2011-08-22T01:19:54Z

On Sun, Aug 21, 2011 at 06:09:00PM -0700, Linus Torvalds wrote:
> On Sun, Aug 21, 2011 at 5:44 PM, Andrew Lutomirski <luto@mit.edu> wrote:
> >
> > Which suggests an easy-ish fix: if sysenter is used or if syscall is
> > entered from the EIP is is supposed to be entered from, then just
> > change ip in the argument save to point to the int 0x80 instruction.
>
> Indeed. Just add an "int 0x80" instruction to the vsyscall thing, and
> you'd be done.
>
> In fact, just replace the
>
> jmp .Lenter_kernel
>
> with
>
> int 0x80
>
> and you'd be pretty much all done, no?

In case of sysenter - almost, in case of syscall - nope...