linux-kernel - Re: [PATCH-RFC 2/2] eventfd: EFD

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:	Tue, 04 Aug 2009 12:30:29 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Gleb Natapov <gleb@...hat.com>
CC:	"Michael S. Tsirkin" <mst@...hat.com>, davidel@...ilserver.org,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH-RFC 2/2] eventfd: EFD_STATE flag

On 08/04/2009 12:23 PM, Gleb Natapov wrote:
> On Tue, Aug 04, 2009 at 12:25:49PM +0300, Avi Kivity wrote:
>    
>> On 08/04/2009 12:17 PM, Gleb Natapov wrote:
>>      
>>>> If a different read comes after the write but after our read, it will
>>>> have transferred the value, resulting in the same situation.
>>>>
>>>> I think reads should never block with a state based mechanism.
>>>>
>>>>
>>>>          
>>> Reader may want to poll for the status change.
>>>
>>>        
>> Without epoll(), it's inherently racy since reads from other processes
>> can clear the status.
>>
>>      
> This is correct for any file descriptor. Multiple readers shouldn't
> simultaneously read from the same files descriptor if they expect to
> make any sense from a result.
>    

I think counting eventfd is an exception, but in general you are right.

-- 
error compiling committee.c: too many arguments to function

--
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/