linux-kernel - Re: [PATCH v2] locking/pvqspinlock: restore/set vcpu_hashed state after failing adaptive locking spinning

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 14 Jul 2016 10:56:30 -0400
From:	Waiman Long <waiman.long@....com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	Wanpeng Li <kernellwp@...il.com>, <linux-kernel@...r.kernel.org>,
	Wanpeng Li <wanpeng.li@...mail.com>,
	Ingo Molnar <mingo@...nel.org>,
	Davidlohr Bueso <dave@...olabs.net>
Subject: Re: [PATCH v2] locking/pvqspinlock: restore/set vcpu_hashed state
 after failing adaptive locking spinning

On 07/14/2016 07:26 AM, Peter Zijlstra wrote:
> On Thu, Jul 14, 2016 at 04:15:56PM +0800, Wanpeng Li wrote:
>> In this case, lock holder inserts the pv_node of queue head into the
>> hash table and set _Q_SLOW_VAL unnecessary. This patch avoids it by
>> restoring/setting vcpu_halted state after failing adaptive locking
>                          ^^^^^^
>> spinning.
>>
>> -		WRITE_ONCE(pn->state, vcpu_halted);
>> +		WRITE_ONCE(pn->state, vcpu_hashed);
>                                             ^^^^^^
>
> The Changelog meant so say vcpu_hashed, surely?

Do you have chance to review the "Fix missed PV wakeup & support PPC" 
patch (https://lkml.org/lkml/2016/5/31/677) that I had sent out a while 
ago? That patch addressed a similar pv_hash leakage and collision problem.

Cheers,
Longman