From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sasha Levin <sasha.levin@oracle.com>
Subject: Re: [PATCH] x86 spinlock: Fix memory corruption on completing
	completions
Date: Fri, 06 Feb 2015 16:15:08 -0500
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References: <1423234148-13886-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com>	
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To: Davidlohr Bueso <dave@stgolabs.net>, Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>, Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>, KVM list <kvm@vger.kernel.org>, Peter Zijlstra <peterz@infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Paul Gortmaker <paul.gortmaker@windriver.com>, Peter Anvin <hpa@zytor.com>, Andi Kleen <ak@linux.intel.com>, Andrey Ryabinin <a.ryabinin@samsung.com>, the arch/x86 maintainers <x86@kernel.org>, Christian Borntraeger <borntraeger@de.ibm.com>, Ingo Molnar <mingo@redhat.com>, xen-devel@lists.xenproject.org, Paul McKenney <paulmck@linux.vnet.ibm.com>, Rik van Riel <riel@redhat.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Dave Jones <davej@redhat.com>, Thomas Gleixner <tglx@linutronix.de>, virtualization <virtualization@lists.linux-foundation.org>, Waiman Long <waiman.long@hp.com>, Oleg Nesterov <oleg@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
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On 02/06/2015 02:42 PM, Davidlohr Bueso wrote:
> On Fri, 2015-02-06 at 08:25 -0800, Linus Torvalds wrote:
>> On Fri, Feb 6, 2015 at 6:49 AM, Raghavendra K T
>> <raghavendra.kt@linux.vnet.ibm.com> wrote:
>>> Paravirt spinlock clears slowpath flag after doing unlock.
>> [ fix edited out ]
>>
>> So I'm not going to be applying this for 3.19, because it's much too
>> late and the patch is too scary. Plus the bug probably effectively
>> never shows up in real life (it is probably easy to trigger the
>> speculative *read* but probably never the actual speculative write
>> after dropping the lock last).
>>
>> This will need a lot of testing by the paravirt people - both
>> performance and correctness. So *maybe* for 3.20, but maybe for even
>> later, and then marked for stable, of course.
>>
>> Are there any good paravirt stress-tests that people could run for
>> extended times?
> 
> locktorture inside a VM should give a proper pounding.

Would it catch lifetime issues too? I thought it just tests out correctness.

I tried it and other unrelated stuff broke. I'll send separate mails for that...


Thanks,
Sasha