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From: Borislav Petkov <bp@alien8.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: "Andy Lutomirski" <luto@amacapital.net>,
	"Kees Cook" <keescook@chromium.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Denys Vlasenko" <vda.linux@googlemail.com>,
	"Brian Gerst" <brgerst@gmail.com>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>,
	"X86 ML" <x86@kernel.org>, "Rik van Riel" <riel@redhat.com>
Subject: Re: [PATCH v2 03/14] notifiers: Assert that RCU is watching in notify_die
Date: Tue, 23 Jun 2015 13:08:44 +0200	[thread overview]
Message-ID: <20150623110844.GG24268@pd.tnic> (raw)
In-Reply-To: <20150623085624.GA2882@gmail.com>

On Tue, Jun 23, 2015 at 10:56:24AM +0200, Ingo Molnar wrote:
> So I think the theory is that crashes do happen, and that any RCU warning only 
> matters to (usually) small race windows.
> 
> So by the time a difficult crash truly happens, exactly in that race window, we'd 
> have fixed the RCU warning long ago.
> 
> I.e. the placement of the RCU warning isn't really relevant in the long run, as it 
> should not trigger.
> 
> In the short run it's probably more important to have it first, because if we have 
> that RCU race then we don't know whether we can trust anything that happens after 
> executing the (flawed) notifier chain.
> 
> Does that logic make sense to you?

Yap, it does actually. Nice :)

Thanks!

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

  reply	other threads:[~2015-06-23 11:09 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-18 19:08 [PATCH v2 00/14] x86: Rewrite exit-to-userspace code Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 01/14] uml: Fix do_signal() prototype Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 02/14] context_tracking: Add ct_state and CT_WARN_ON Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 03/14] notifiers: Assert that RCU is watching in notify_die Andy Lutomirski
2015-06-22 11:36   ` Borislav Petkov
2015-06-22 16:26     ` Andy Lutomirski
2015-06-22 16:33       ` Borislav Petkov
2015-06-22 17:03         ` Andy Lutomirski
2015-06-22 17:24           ` Borislav Petkov
2015-06-22 17:37             ` Andy Lutomirski
2015-06-22 18:15               ` Borislav Petkov
2015-06-22 19:48                 ` Andy Lutomirski
2015-06-23  8:56         ` Ingo Molnar
2015-06-23 11:08           ` Borislav Petkov [this message]
2015-06-18 19:08 ` [PATCH v2 04/14] x86: Move C entry and exit code to arch/x86/entry/common.c Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 05/14] x86/traps: Assert that we're in CONTEXT_KERNEL in exception entries Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 06/14] x86/entry: Add enter_from_user_mode and use it in syscalls Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 07/14] x86/entry: Add new, comprehensible entry and exit hooks Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 08/14] x86/entry/64: Really create an error-entry-from-usermode code path Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 09/14] x86/entry/64: Migrate 64-bit and compat syscalls to new exit hooks Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 10/14] x86/asm/entry/64: Save all regs on interrupt entry Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 11/14] x86/asm/entry/64: Simplify irq stack pt_regs handling Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 12/14] x86/asm/entry/64: Migrate error and interrupt exit work to C Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 13/14] x86/entry: Remove exception_enter from trap handlers Andy Lutomirski
2015-06-18 19:08 ` [PATCH v2 14/14] x86/entry: Remove SCHEDULE_USER and asm/context-tracking.h Andy Lutomirski
2015-06-22 19:50 ` [PATCH v2 00/14] x86: Rewrite exit-to-userspace code Andy Lutomirski
2015-06-23  5:32   ` Andy Lutomirski

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