From: Thomas Gleixner <tglx@linutronix.de>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
"H. Peter Anvin" <hpa@zytor.com>,
the arch/x86 maintainers <x86@kernel.org>,
"Xen-devel@lists.xensource.com" <Xen-devel@lists.xensource.com>,
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>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH] fix pgd_lock deadlock
Date: Tue, 15 Feb 2011 20:26:51 +0100 (CET) [thread overview]
Message-ID: <alpine.LFD.2.00.1102152020590.26192@localhost6.localdomain6> (raw)
In-Reply-To: <20110215190710.GL5935@random.random>
On Tue, 15 Feb 2011, Andrea Arcangeli wrote:
> Hello,
>
> Without this patch we can deadlock in the page_table_lock with NR_CPUS
> < 4 or THP on, with this patch we hopefully won't deadlock in the
> pgd_lock (if taken from irq). I can't see anything taking it from irq
> (maybe aio? to check I also tried the libaio testuite with no apparent
> VM_BUG_ON triggering), so unless somebody sees it, I think we should
> apply it. I've been running for a while with this patch applied
> without apparent problems. Other archs may follow suit if it's proven
> that there's nothing taking the pgd_lock from irq.
>
> ===
> 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.
I really read this thing 5 times and still cannot make any sense of it.
You talk about page_table_lock and then fiddle with pgd_lock.
-ENOSENSE
tglx
next prev parent reply other threads:[~2011-02-15 19:28 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-14 20:56 [PATCH] x86: hold mm->page_table_lock while doing vmalloc_sync Jeremy Fitzhardinge
2010-10-15 17:07 ` [Xen-devel] " Jeremy Fitzhardinge
2010-10-19 22:17 ` [tip:x86/mm] x86, mm: Hold " tip-bot for Jeremy Fitzhardinge
2010-10-20 10:36 ` Borislav Petkov
2010-10-20 19:31 ` [tip:x86/mm] x86, mm: Fix incorrect data type in vmalloc_sync_all() tip-bot for tip-bot for Jeremy Fitzhardinge
2010-10-20 19:50 ` Borislav Petkov
2010-10-20 19:53 ` H. Peter Anvin
2010-10-20 20:10 ` Borislav Petkov
2010-10-20 20:13 ` H. Peter Anvin
2010-10-20 22:11 ` Borislav Petkov
2010-10-20 21:26 ` Ben Pfaff
2010-10-20 19:58 ` tip-bot for Borislav Petkov
2010-10-21 21:06 ` [PATCH] x86: hold mm->page_table_lock while doing vmalloc_sync Jeremy Fitzhardinge
2010-10-21 21:26 ` H. Peter Anvin
2010-10-21 21:34 ` Jeremy Fitzhardinge
2011-02-03 2:48 ` Andrea Arcangeli
2011-02-03 20:44 ` Jeremy Fitzhardinge
2011-02-04 1:21 ` Andrea Arcangeli
2011-02-04 21:27 ` Jeremy Fitzhardinge
2011-02-07 23:20 ` Andrea Arcangeli
2011-02-15 19:07 ` [PATCH] fix pgd_lock deadlock Andrea Arcangeli
2011-02-15 19:26 ` Thomas Gleixner [this message]
2011-02-15 19:54 ` Andrea Arcangeli
2011-02-15 20:05 ` Thomas Gleixner
2011-02-15 20:26 ` Thomas Gleixner
2011-02-15 22:52 ` Andrea Arcangeli
2011-02-15 23:03 ` Thomas Gleixner
2011-02-15 23:17 ` Andrea Arcangeli
2011-02-16 9:58 ` Peter Zijlstra
2011-02-16 10:15 ` Andrea Arcangeli
2011-02-16 10:28 ` Ingo Molnar
2011-02-16 14:49 ` Andrea Arcangeli
2011-02-16 16:26 ` Rik van Riel
2011-02-16 20:15 ` Ingo Molnar
2012-04-23 9:07 ` [2.6.32.y][PATCH] " Philipp Hahn
2012-04-23 19:09 ` Willy Tarreau
2011-02-16 18:33 ` [PATCH] " Andrea Arcangeli
2011-02-16 21:34 ` Konrad Rzeszutek Wilk
2011-02-17 10:19 ` Johannes Weiner
2011-02-21 14:30 ` Andrea Arcangeli
2011-02-21 14:53 ` Johannes Weiner
2011-02-22 7:48 ` Jan Beulich
2011-02-22 13:49 ` Andrea Arcangeli
2011-02-22 14:22 ` Jan Beulich
2011-02-22 14:34 ` Andrea Arcangeli
2011-02-22 17:08 ` Jeremy Fitzhardinge
2011-02-22 17:13 ` Andrea Arcangeli
2011-02-24 4:22 ` Andrea Arcangeli
2011-02-24 8:23 ` Jan Beulich
2011-02-24 14:11 ` Andrea Arcangeli
2011-02-21 17:40 ` Jeremy Fitzhardinge
2011-02-03 20:59 ` [PATCH] x86: hold mm->page_table_lock while doing vmalloc_sync Larry Woodman
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