linux-kernel - Re: [RFC][PATCH 4/7] x86/debug: Move historical SYSENTER junk into exc_debug

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200820172118.n5injemo3ic63x6j@treble>
Date:   Thu, 20 Aug 2020 12:21:18 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Andy Lutomirski <luto@...capital.net>
Cc:     peterz@...radead.org, Brian Gerst <brgerst@...il.com>,
        the arch/x86 maintainers <x86@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Kyle Huey <me@...ehuey.com>,
        Alexandre Chartre <alexandre.chartre@...cle.com>,
        Robert O'Callahan <rocallahan@...il.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Andy Lutomirski <luto@...nel.org>
Subject: Re: [RFC][PATCH 4/7] x86/debug: Move historical SYSENTER junk into
 exc_debug_kernel()

On Thu, Aug 20, 2020 at 09:43:15AM -0700, Andy Lutomirski wrote:
> 
> 
> > On Aug 20, 2020, at 9:35 AM, peterz@...radead.org wrote:
> > 
> > On Thu, Aug 20, 2020 at 11:17:29AM -0500, Josh Poimboeuf wrote:
> >> On Thu, Aug 20, 2020 at 05:21:11PM +0200, peterz@...radead.org wrote:
> > 
> >>> qemu-gdb stub should eat the event before it lands in the guest
> >> 
> >> Are we sure about that?  I triggered the warning just now, stepping
> >> through the debug handler.
> > 
> > Not sure at all, that's what seemed reasonable, but since when did that
> > stop virt ;-)
> > 
> > Also, can you trigger that same with upstream? Because I suspect this
> > ought to tickle the old code too.
> 
> I’ve lost track of how many bugs QEMU and KVM have in this space.
> Let’s keep it as a warning, but a bug. But let’s get rid of the
> totally bogus TIF_SINGLESTEP manipulation.

By "but a bug", I assume you mean "not a bug" :-)

-- 
Josh