Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 4 Jul 2023 14:21:25 +0100
From:   "Richard W.M. Jones" <rjones@redhat.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        Anders Roxell <anders.roxell@linaro.org>,
        Daniel =?iso-8859-1?Q?D=EDaz?= <daniel.diaz@linaro.org>,
        Benjamin Copeland <ben.copeland@linaro.org>,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        Richard Henderson <richard.henderson@linaro.org>
Subject: Re: qemu-x86_64 booting with 8.0.0 stil see int3: when running LTP
 tracing testing.
Message-ID: <20230704132125.GB17440@redhat.com>
References: <CA+G9fYsETJQm0Ue7hGsb+nbsiMikwycOV3V0DPr6WC2r61KRBQ@mail.gmail.com>
 <2d7595b1-b655-4425-85d3-423801bce644@app.fastmail.com>
 <20230621160655.GL2053369@hirez.programming.kicks-ass.net>
 <20230704074620.GA17440@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230704074620.GA17440@redhat.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Precedence: bulk

On Tue, Jul 04, 2023 at 08:46:20AM +0100, Richard W.M. Jones wrote:
> We have been having the same sort of problem
> (https://bugzilla.redhat.com/show_bug.cgi?id=2216496).  It's another
> of those bugs that requires hundreds or thousands of boot iterations
> before you can see it.  There is a test in comment 27 but it requires
> guestfish and some hacking to work.  I'll try to come up with a
> cleaner test later.

FWIW here's a better test.  It only uses qemu-system-x86_64 & a
vmlinuz file of your choice, and is very fast.  It usually hits the
bug in seconds.

  https://github.com/rwmjones/bootbootboot/tree/bz2216496

NB: You will need to change the definition of VMLINUX in
config-bz2216496-qemu.h (and generally read the code before running,
but hopefully it should just work apart from choosing a kernel image).

> I'd love to have a better way to debug this or collect more
> diagnostics if you have any suggestions.

Still open to any suggestions about better ways to debug this, or
anything you'd like me to try out.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html