netdev - Re: [Xen-devel] [PATCH net] xen-netback: add the scenario which now beyond the range time_after

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]

Message-ID: <20131017164127.GA11894@zion.uk.xensource.com>
Date:	Thu, 17 Oct 2013 17:41:27 +0100
From:	Wei Liu <wei.liu2@...rix.com>
To:	annie li <annie.li@...cle.com>
CC:	Jan Beulich <JBeulich@...e.com>,
	jianhai luan <jianhai.luan@...cle.com>,
	<david.vrabel@...rix.com>, <ian.campbell@...rix.com>,
	<wei.liu2@...rix.com>, <xen-devel@...ts.xenproject.org>,
	<netdev@...r.kernel.org>
Subject: Re: [Xen-devel] [PATCH net] xen-netback: add the scenario which now
 beyond the range time_after_eq().

On Fri, Oct 18, 2013 at 12:38:12AM +0800, annie li wrote:
> 
> On 2013-10-17 17:26, Jan Beulich wrote:
> >>Yes, the issue only can be  reproduced in 32-bit Dom0 (Beyond
> >>MAX_ULONG/2 in 64-bit will need long long time)
> >>
> >>I think the gap should be think all environment even now extending 480+.
> >>if now fall in the gap,  one timer will be pending and replenish will be
> >>in time.  Please run the attachment test program.
> >Not sure what this is supposed to tell me. I recognize that there
> >are overflow conditions not handled properly, but (a) I have a
> >hard time thinking of a sensible guest that sits idle for over 240
> >days (host uptime usually isn't even coming close to that due to
> >maintenance requirements) and (b) if there is such a sensible
> >guest, then I can't see why dealing with one being idle for over
> >480 days should be required too.
> >
> 
> If the guest contains multiple NICs, that situation probably happens
> when one NIC keeps idle and others work under load. BTW, how do you
> get the 240?
> 

I think Jan got this number with HZ=100. It take ~240 days for jiffies
to overflow in 32 bit machine when HZ=100.

Wei.

> Thanks
> Annie
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html