linux-kernel - Re: [PATCH] KVM: x86: Kick VCPU outside PIC lock again

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:	Wed, 24 Feb 2010 10:54:45 +0100
From:	Jan Kiszka <jan.kiszka@...mens.com>
To:	Avi Kivity <avi@...hat.com>
CC:	Thomas Gleixner <tglx@...utronix.de>, KVM <kvm@...r.kernel.org>,
	Gleb Natapov <gleb@...hat.com>,
	RT <linux-rt-users@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] KVM: x86: Kick VCPU outside PIC lock again

Avi Kivity wrote:
> On 02/24/2010 11:41 AM, Jan Kiszka wrote:
>> Thomas Gleixner wrote:
>>    
>>> On Tue, 23 Feb 2010, Jan Kiszka wrote:
>>>
>>>      
>>>> Thomas Gleixner wrote:
>>>>        
>>>>> The i8254/i8259 locks need to be real spinlocks on preempt-rt. Convert
>>>>> them to raw_spinlock. No change for !RT kernels.
>>>>>          
>>>> Doesn't fly for -rt anymore: pic_irq_update runs under this raw lock and
>>>> calls kvm_vcpu_kick which tries to wake_up some thread ->  scheduling
>>>> while atomic.
>>>>        
>>> Hmm, a wakeup itself is fine. Is that code waking a wake queue ?
>>>      
>> Yes, it's a wake queue.
>>    
> 
> So what's the core issue?  Is the lock_t in the wait_queue a sleeping mutex?

Yep.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/