From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>,
tdevries@suse.com, x86-ml <x86@kernel.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: gdbserver + fsgsbase kaputt
Date: Mon, 11 Jan 2021 21:00:27 +0100 [thread overview]
Message-ID: <20210111200027.GH25645@zn.tnic> (raw)
In-Reply-To: <CALCETrV98776mNd20v8r+JXt0uOUKemd_YnDYDoLXN_LDfQnog@mail.gmail.com>
On Mon, Jan 11, 2021 at 11:27:38AM -0800, Andy Lutomirski wrote:
> Hmm. Can you try booting with unsafe_fsgsbase and bisecting further?
Well, that bisection ended in that patch:
# first bad commit: [b745cfba44c152c34363eea9e052367b6b1d652b] x86/cpu: Enable FSGSBASE on 64bit by default and add a chicken bit
so I can't go further.
Or do you mean I should add "unsafe_fsgsbase" to grub cmdline and bisect
with fsgsbase enabled in all test kernels?
> And maybe send me your test binary?
It is trivial:
int
main (void)
{
return 0;
}
how can that make any difference or are you thinking compiler differences?
Lemme send it to you.
> I tried to reproduce this, but it worked fine, even if I compile the
> test program with -fstack-protector-all.
Hmm.
> Off the top of my head, I would have expected this to fix it:
>
> commit 40c45904f818c1f6555294ca27afc5fda4f09e68
> Author: Andy Lutomirski <luto@kernel.org>
> Date: Fri Jun 26 10:24:29 2020 -0700
>
> x86/ptrace: Fix 32-bit PTRACE_SETREGS vs fsbase and gsbase
More hmm.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-01-11 20:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 18:15 Borislav Petkov
2021-01-11 19:27 ` Andy Lutomirski
2021-01-11 20:00 ` Borislav Petkov [this message]
2021-01-11 21:06 ` Andy Lutomirski
2021-01-11 23:40 ` Andy Lutomirski
2021-01-11 23:52 ` Tom de Vries
2021-01-12 3:31 ` Andy Lutomirski
2021-01-12 8:45 ` Tom de Vries
2021-01-12 6:15 ` Bae, Chang Seok
2021-01-12 11:39 ` Metzger, Markus T
2021-01-12 16:53 ` Andy Lutomirski
2021-01-12 17:02 ` Metzger, Markus T
2021-01-12 17:13 ` Andy Lutomirski
2021-01-20 15:42 ` Metzger, Markus T
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