linux-kernel - Re: vmstat: On demand vmstat workers V8

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: <alpine.DEB.2.11.1407291024300.21390@gentwo.org>
Date:	Tue, 29 Jul 2014 10:26:08 -0500 (CDT)
From:	Christoph Lameter <cl@...two.org>
To:	Tejun Heo <tj@...nel.org>
cc:	Peter Zijlstra <peterz@...radead.org>,
	Sasha Levin <sasha.levin@...cle.com>,
	akpm@...ux-foundation.org, Gilad Ben-Yossef <gilad@...yossef.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	John Stultz <johnstul@...ibm.com>,
	Mike Frysinger <vapier@...too.org>,
	Minchan Kim <minchan.kim@...il.com>,
	Hakan Akkan <hakanakkan@...il.com>,
	Max Krasnyansky <maxk@...lcomm.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, hughd@...gle.com,
	viresh.kumar@...aro.org, hpa@...or.com, mingo@...nel.org,
	Lai Jiangshan <laijs@...fujitsu.com>
Subject: Re: vmstat: On demand vmstat workers V8

On Tue, 29 Jul 2014, Tejun Heo wrote:

> > mm/vmstat.c already has cpu down hooks. See vmstat_cpuup_callback().
>
> Hmmm, well, then it's something else.  Either a bug in workqueue or in
> the caller.  Given the track record, the latter is more likely.
> e.g. it looks kinda suspicious that the work func is cleared after
> cancel_delayed_work_sync() is called.  What happens if somebody tries

Ok we can clear it before then.

Just looked at the current upstream code. It also does a __this_cpu_read()
in refresh_cpu_stats() without triggering the preemption check. What
changed in -next that made the test trigger now?

--
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/