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From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
	Alexandre Chartre <alexandre.chartre@oracle.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, "Paul E. McKenney" <paulmck@kernel.org>,
	Andy Lutomirski <luto@kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>, Brian Gerst <brgerst@gmail.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Will Deacon <will@kernel.org>
Subject: Re: [patch V4 part 4 15/24] x86/db: Split out dr6/7 handling
Date: Fri, 08 May 2020 13:58:30 +0200	[thread overview]
Message-ID: <87wo5mk595.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200508085909.GU5298@hirez.programming.kicks-ass.net>

Peter Zijlstra <peterz@infradead.org> writes:
>> > +static __always_inline void debug_enter(unsigned long *dr6, unsigned long *dr7)
>> > +{
>> > +	/*
>> > +	 * Disable breakpoints during exception handling; recursive exceptions
>> > +	 * are exceedingly 'fun'.
>> > +	 *
>> > +	 * Since this function is NOKPROBE, and that also applies to
>> > +	 * HW_BREAKPOINT_X, we can't hit a breakpoint before this (XXX except a
>> > +	 * HW_BREAKPOINT_W on our stack)
>> > +	 *
>> > +	 * Entry text is excluded for HW_BP_X and cpu_entry_area, which
>> > +	 * includes the entry stack is excluded for everything.
>> > +	 */
>> > +	get_debugreg(*dr7, 6);
>> 
>> Do you mean  get_debugreg(*dr7, 7); ?
>
> Shees, I have to go buy a new stack of brown paper bags at this rate,
> don't I :/

Not only you, but it's also  amazing that the selftests didn't catch
that.

  reply	other threads:[~2020-05-08 11:59 UTC|newest]

Thread overview: 94+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 13:49 [patch V4 part 4 00/24] x86/entry: Entry/exception code rework, nasty exceptions Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 01/24] x86/int3: Ensure that poke_int3_handler() is not traced Thomas Gleixner
2020-05-14  4:57   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 02/24] x86/int3: Avoid atomic instrumentation Thomas Gleixner
2020-05-08 13:27   ` Masami Hiramatsu
2020-05-14  4:57   ` Andy Lutomirski
2020-05-14  9:32     ` Peter Zijlstra
2020-05-14 12:51       ` Thomas Gleixner
2020-05-14 13:15         ` Peter Zijlstra
2020-05-14 14:55           ` Andy Lutomirski
2020-05-14 15:06           ` Thomas Gleixner
2020-05-14 15:08             ` Andy Lutomirski
2020-05-14 15:10               ` Peter Zijlstra
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:49 ` [patch V4 part 4 03/24] lib/bsearch: Provide __always_inline variant Thomas Gleixner
2020-05-14  4:58   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:49 ` [patch V4 part 4 04/24] x86/int3: Inline bsearch() Thomas Gleixner
2020-05-14  4:58   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:49 ` [patch V4 part 4 05/24] x86/entry: Provide IDTENTRY_RAW Thomas Gleixner
2020-05-14  4:59   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] x86/idtentry: " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 06/24] x86/entry: Convert INT3 exception to IDTENTRY_RAW Thomas Gleixner
2020-05-14  5:01   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 07/24] x86/traps: Split int3 handler up Thomas Gleixner
2020-05-14  5:03   ` Andy Lutomirski
2020-05-14  9:39     ` Peter Zijlstra
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:49 ` [patch V4 part 4 08/24] x86/entry: Provide IDTENTRY_IST Thomas Gleixner
2020-05-14 16:39   ` Andy Lutomirski
2020-05-14 18:44     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] x86/idtentry: " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 09/24] x86/mce: Move nmi_enter/exit() into the entry point Thomas Gleixner
2020-05-15  5:23   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 10/24] x86/entry: Convert Machine Check to IDTENTRY_IST Thomas Gleixner
2020-05-15  5:24   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 11/24] x86/mce: Use untraced rd/wrmsr in the MCE offline/crash check Thomas Gleixner
2020-05-15  5:24   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 12/24] x86/idtentry: Provide IDTENTRY_XEN for XEN/PV Thomas Gleixner
2020-05-15  5:25   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 13/24] x86/entry: Convert NMI to IDTENTRY_NMI Thomas Gleixner
2020-05-15  5:26   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 14/24] x86/nmi: Protect NMI entry against instrumentation Thomas Gleixner
2020-05-15  5:26   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 15/24] x86/db: Split out dr6/7 handling Thomas Gleixner
2020-05-07 17:18   ` Alexandre Chartre
2020-05-08  8:59     ` Peter Zijlstra
2020-05-08 11:58       ` Thomas Gleixner [this message]
2020-05-08 12:45         ` Peter Zijlstra
2020-05-14  2:24   ` Mathieu Desnoyers
2020-05-14 17:28     ` Thomas Gleixner
2020-05-14 17:46       ` Mathieu Desnoyers
2020-05-15 14:32         ` Thomas Gleixner
2020-05-14 18:06     ` Steven Rostedt
2020-05-15  5:37   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-05 13:49 ` [patch V4 part 4 16/24] x86/entry: Convert Debug exception to IDTENTRY_DB Thomas Gleixner
2020-05-15  5:27   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 17/24] x86/entry/64: Remove error code clearing from #DB and #MCE ASM stub Thomas Gleixner
2020-05-15  5:27   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 18/24] x86/entry: Provide IDTRENTRY_NOIST variants for #DB and #MC Thomas Gleixner
2020-05-15  5:29   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] x86/idtentry: " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 19/24] x86/entry: Implement user mode C entry points for #DB and #MCE Thomas Gleixner
2020-05-15  5:32   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 20/24] x86/traps: Restructure #DB handling Thomas Gleixner
2020-05-15  5:39   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 21/24] x86/traps: Address objtool noinstr complaints in #DB Thomas Gleixner
2020-05-15  5:39   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 22/24] x86/mce: Address objtools noinstr complaints Thomas Gleixner
2020-05-15  5:40   ` Andy Lutomirski
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 23/24] x86/entry: Provide IDTENTRY_DF Thomas Gleixner
2020-05-15  5:41   ` Andy Lutomirski
2020-05-15 15:01     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] x86/idtentry: " tip-bot2 for Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] x86/entry: Convert double fault exception to IDTENTRY_DF tip-bot2 for Thomas Gleixner
2020-05-05 13:49 ` [patch V4 part 4 24/24] " Thomas Gleixner
2020-05-07 19:55   ` Alexandre Chartre
2020-05-15  5:42   ` Andy Lutomirski

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