From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Will Deacon <Will.Deacon@arm.com>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
lkml <linux-kernel@vger.kernel.org>,
Noam Camus <noamc@ezchip.com>,
arcml <linux-snps-arc@lists.infradead.org>
Subject: Re: Interesting csd deadlock on ARC
Date: Thu, 25 Feb 2016 14:30:46 +0000 [thread overview]
Message-ID: <20160225143046.GR19428@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <56CF0E6B.5020903@synopsys.com>
On Thu, Feb 25, 2016 at 07:53:39PM +0530, Vineet Gupta wrote:
> But then ARM CONFIG_SMP on UP hardware will still crap out because there
> is no way to send IPI to self. Same as the bug in above discussion. I'm
> surprised they way ARM guys worked around it.
We haven't worked around it - the code which provoked the oops that was
seen (in the cpufreq code) was changed not to call it, which has the
effect of making the problem "go away", at least for now.
We still have the problem that if it does get called on UP, it'll blow
up - and I don't see any point in complicating the code for something
that never happens right now.
--
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
WARNING: multiple messages have this Message-ID (diff)
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-snps-arc@lists.infradead.org
Subject: Interesting csd deadlock on ARC
Date: Thu, 25 Feb 2016 14:30:46 +0000 [thread overview]
Message-ID: <20160225143046.GR19428@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <56CF0E6B.5020903@synopsys.com>
On Thu, Feb 25, 2016@07:53:39PM +0530, Vineet Gupta wrote:
> But then ARM CONFIG_SMP on UP hardware will still crap out because there
> is no way to send IPI to self. Same as the bug in above discussion. I'm
> surprised they way ARM guys worked around it.
We haven't worked around it - the code which provoked the oops that was
seen (in the cpufreq code) was changed not to call it, which has the
effect of making the problem "go away", at least for now.
We still have the problem that if it does get called on UP, it'll blow
up - and I don't see any point in complicating the code for something
that never happens right now.
--
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2016-02-25 14:31 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-19 6:47 Interesting csd deadlock on ARC Vineet Gupta
2016-02-19 6:47 ` Vineet Gupta
2016-02-23 5:21 ` Vineet Gupta
2016-02-23 5:21 ` Vineet Gupta
2016-02-23 9:58 ` Peter Zijlstra
2016-02-23 9:58 ` Peter Zijlstra
2016-02-23 9:58 ` Peter Zijlstra
2016-02-23 10:21 ` Vineet Gupta
2016-02-23 10:21 ` Vineet Gupta
2016-02-23 10:39 ` Peter Zijlstra
2016-02-23 10:39 ` Peter Zijlstra
2016-02-23 10:58 ` Noam Camus
2016-02-23 10:58 ` Noam Camus
2016-02-23 10:58 ` Noam Camus
2016-02-24 4:45 ` Vineet Gupta
2016-02-24 4:45 ` Vineet Gupta
2016-02-24 4:51 ` Vineet Gupta
2016-02-24 4:51 ` Vineet Gupta
2016-02-25 14:06 ` Peter Zijlstra
2016-02-25 14:06 ` Peter Zijlstra
2016-02-25 14:06 ` Peter Zijlstra
2016-02-25 14:23 ` Vineet Gupta
2016-02-25 14:23 ` Vineet Gupta
2016-02-25 14:30 ` Russell King - ARM Linux [this message]
2016-02-25 14:30 ` Russell King - ARM Linux
2016-02-25 15:58 ` Vineet Gupta
2016-02-25 15:58 ` Vineet Gupta
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