Re: [User-mode-linux-user] Ptrace broken since 2.4.0-test8pre4?...

From: William Stearns (wstearns@pobox.com)
Date: Thu Sep 21 2000 - 12:08:39 EST


On Tue, 19 Sep 2000, Jeff Dike wrote:

> yur@asplinux.ru said:
> > I tested vanilla test7 with ptrace() patch. It breaks uml exactly
> > like I see with any kernel > test7.
>
> > exec_user.c:29 ptrace(PTRACE_SYSCALL, 4901, 0, 0) = 0
> > And voila, we got SIGSEGV instead of happy running child:
> > Child 4901 exited with signal 11
>
> Yuri, I apologize for doubting you. That's about the best evidence possible
> that the test8 ptrace fix is what's breaking UML and not the thread group
> stuff.
>
> If anyone has any idea why that fix breaks PTRACE_SYSCALL, I'd love to know.
> I'm kind of short on time at the moment, so I'm not in a great position to
> delve into this at the moment.
>
> Until this is fixed, UML doesn't work on any host kernels beyond test7.

        As a further verification that this change is causing problems for
UML, test9-pre5 allows uml to run if the ptrace.c change is
reverted. I do understand that this is not the correct fix for the
problem, but for those who would like to independently verify this, the
(incorrect) patch is attached.

        Cheers,
        - Bill

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--------------------------------------------------------------------------
William Stearns (wstearns@pobox.com). Mason, Buildkernel, named2hosts,
and ipfwadm2ipchains are at: http://www.pobox.com/~wstearns
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