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Date:   Thu, 23 Jul 2020 16:52:20 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        linux-kernel@vger.kernel.org
Subject: Re: Regression on todays tip/master (commit 16f70beccf43)
Message-ID: <20200723145219.GP27672@8bytes.org>
References: <20200723133743.GA30716@8bytes.org>
 <871rl2xpar.fsf@nanos.tec.linutronix.de>
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On Thu, Jul 23, 2020 at 04:46:04PM +0200, Thomas Gleixner wrote:
> Joerg Roedel <joro@8bytes.org> writes:
> > while testing the SEV-ES patches on todays tip/master I triggered the BUG
> > below:
> >
> > [  137.629660] ------------[ cut here ]------------
> > [  137.630769] kernel BUG at kernel/signal.c:1917!
> > [  137.631796] invalid opcode: 0000 [#1] SMP NOPTI
> > [  137.632822] CPU: 3 PID: 28596 Comm: test_syscall_vd Not tainted 5.8.0-rc6-tip+ #3
> > [  137.634495] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
> > [  137.636236] RIP: 0010:do_notify_parent+0x25c/0x290
> > The guest had 4 VCPUs and ran 4 instances of the in-kernel x86-selftests
> > in a loop, together with 'perf top -e cycles:k'. As you can see in the
> > time-stamps, the issue triggered pretty quickly.
> >
> > Please let me know if you need more information or testing from my side.
> 
> Any chance to bisect this?

Yes, will try. I am currently testing plain -rc6, it seems to be fine.
Bisecting is next.