linux-kernel - Re: [PATCH] ksoftirqd: Enable IRQs and call cond

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: <1421821779.16275.5.camel@marge.simpson.net>
Date:	Wed, 21 Jan 2015 07:29:39 +0100
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	paulmck@...ux.vnet.ibm.com
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Calvin Owens <calvinowens@...com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Joe Perches <joe@...ches.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org, kernel-team@...com
Subject: Re: [PATCH] ksoftirqd: Enable IRQs and call cond_resched() before
 poking RCU

On Tue, 2015-01-20 at 21:10 -0800, Paul E. McKenney wrote: 
> On Wed, Jan 21, 2015 at 04:40:39AM +0100, Mike Galbraith wrote:

> > I've been curious about this for ages, so now is a great time to bite
> > the bullet and ask TheMan.  A context switch is not far away, why do we
> > need that quiescent state badly enough to tell what looks like a little
> > white lie to get it immediately?
> > 
> > (I commented it out in an -rt kernel I was testing yesterday, beat it
> > enthusiastically for a while, and box didn't _seem_ to notice that it
> > was missing anything)
> 
> Yeah, you do have to have a fairly violent network-based DoS attack
> to see the difference.  Robert Olsson was the first to make this happen
> back in the day.

Ah, my little NIC doesn't have enough poop to do that.  Thanks.

-Mike

--
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/