Message-ID: <4D5BFAB7.5070504@redhat.com>
Date: Wed, 16 Feb 2011 11:26:31 -0500
From: Rik van Riel <riel@redhat.com>
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To: Andrea Arcangeli <aarcange@redhat.com>
CC: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jeremy Fitzhardinge <jeremy@goop.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        the arch/x86 maintainers <x86@kernel.org>,
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        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Ian Campbell <Ian.Campbell@citrix.com>,
        Jan Beulich <JBeulich@novell.com>, Larry Woodman <lwoodman@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>, Andi Kleen <ak@suse.de>,
        Johannes Weiner <jweiner@redhat.com>, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] fix pgd_lock deadlock
References: <alpine.LFD.2.00.1102152020590.26192@localhost6.localdomain6> <20110215195450.GO5935@random.random> <alpine.LFD.2.00.1102152102530.26192@localhost6.localdomain6> <alpine.LFD.2.00.1102152125180.26192@localhost6.localdomain6> <20110215225234.GP5935@random.random> <alpine.LFD.2.00.1102160002300.26192@localhost6.localdomain6> <20110215231733.GR5935@random.random> <1297850294.2413.30.camel@twins> <20110216101521.GU5935@random.random> <20110216102801.GA23082@elte.hu> <20110216144947.GA5935@random.random>
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On 02/16/2011 09:49 AM, Andrea Arcangeli wrote:

> Subject: fix pgd_lock deadlock
>
> From: Andrea Arcangeli<aarcange@redhat.com>
>
> It's forbidden to take the page_table_lock with the irq disabled or if there's
> contention the IPIs (for tlb flushes) sent with the page_table_lock held will
> never run leading to a deadlock.
>
> Apparently nobody takes the pgd_lock from irq so the _irqsave can be removed.
>
> Signed-off-by: Andrea Arcangeli<aarcange@redhat.com>


Acked-by: Rik van Riel <riel@redhat.com>
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