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Date:   Mon, 10 Aug 2020 16:06:48 +0200
From:   peterz@infradead.org
To:     Marco Elver <elver@google.com>
Cc:     "Paul E. McKenney" <paulmck@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        LKML <linux-kernel@vger.kernel.org>,
        syzbot <syzbot+8db9e1ecde74e590a657@syzkaller.appspotmail.com>
Subject: Re: [PATCH] kcsan: Treat runtime as NMI-like with interrupt tracing
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References: <20200807090031.3506555-1-elver@google.com>
 <20200807170618.GW4295@paulmck-ThinkPad-P72>
 <CANpmjNPqEeQvg53wJ5EsyfssSqyOqCsPG+YTV6ytj6wsc+5BPQ@mail.gmail.com>
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On Mon, Aug 10, 2020 at 10:07:44AM +0200, Marco Elver wrote:
> On Fri, 7 Aug 2020 at 19:06, Paul E. McKenney <paulmck@kernel.org> wrote:
> > On Fri, Aug 07, 2020 at 11:00:31AM +0200, Marco Elver wrote:
> > > Since KCSAN instrumentation is everywhere, we need to treat the hooks
> > > NMI-like for interrupt tracing. In order to present an as 'normal' as
> > > possible context to the code called by KCSAN when reporting errors, we
> > > need to update the IRQ-tracing state.
> > >
> > > Tested: Several runs through kcsan-test with different configuration
> > > (PROVE_LOCKING on/off), as well as hours of syzbot testing with the
> > > original config that caught the problem (without CONFIG_PARAVIRT=y,
> > > which appears to cause IRQ state tracking inconsistencies even when
> > > KCSAN remains off, see Link).
> > >
> > > Link: https://lkml.kernel.org/r/0000000000007d3b2d05ac1c303e@google.com
> > > Fixes: 248591f5d257 ("kcsan: Make KCSAN compatible with new IRQ state tracking")
> > > Reported-by: syzbot+8db9e1ecde74e590a657@syzkaller.appspotmail.com
> > > Co-developed-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> 
> Peter, if you're fine with it, I think we'll require your
> Signed-off-by (since Co-developed-by).

Sure:

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>