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Date: Fri, 23 Jan 2015 19:04:55 +0100
From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Sasha Levin <sasha.levin@oracle.com>, X86 ML <x86@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Josh Triplett <josh@joshtriplett.org>,
        =?utf-8?B?RnLDqWTDqXJpYw==?= Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH v4 2/5] x86, traps: Track entry into and exit from IST
 context
Message-ID: <20150123180455.GA3192@pd.tnic>
References: <cover.1416604491.git.luto@amacapital.net>
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On Fri, Jan 23, 2015 at 09:58:01AM -0800, Andy Lutomirski wrote:
> > [  543.999079] Call Trace:
> > [  543.999079] dump_stack (lib/dump_stack.c:52)
> > [  543.999079] lockdep_rcu_suspicious (kernel/locking/lockdep.c:4259)
> > [  543.999079] atomic_notifier_call_chain (include/linux/rcupdate.h:892 kernel/notifier.c:182 kernel/notifier.c:193)
> > [  543.999079] ? atomic_notifier_call_chain (kernel/notifier.c:192)
> > [  543.999079] notify_die (kernel/notifier.c:538)
> > [  543.999079] ? atomic_notifier_call_chain (kernel/notifier.c:538)
> > [  543.999079] ? debug_smp_processor_id (lib/smp_processor_id.c:57)
> > [  543.999079] do_debug (arch/x86/kernel/traps.c:652)
> > [  543.999079] ? trace_hardirqs_on (kernel/locking/lockdep.c:2609)
> > [  543.999079] ? do_int3 (arch/x86/kernel/traps.c:610)
> > [  543.999079] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2554 kernel/locking/lockdep.c:2601)
> > [  543.999079] debug (arch/x86/kernel/entry_64.S:1310)
> 
> I don't know how to read this stack trace.  Are we in do_int3,
> do_debug, or both?  I didn't change do_debug at all.

It looks like we're in do_debug. do_int3 is only on the stack but not
part of the current frame if I can trust the '?' ...

-- 
Regards/Gruss,
    Boris.

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