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From: Martin Steigerwald <martin.steigerwald@teamix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>, Andrew Morton <akpm@osdl.org>,
        Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
        Nicolas Dichtel <nicolas.dichtel@6wind.com>,
        Jay Lan <jlan@engr.sgi.com>, Martin Steigerwald <martin@lichtvoll.de>,
        Gerlof Langeveld <gerlof.langeveld@atoptool.nl>,
        Marc Haber <mh+debian-packages@zugschlus.de>,
        Ben Hutchings <ben@decadent.org.uk>,
        Balbir Singh <bsingharora@gmail.com>, Tejun Heo <tj@kernel.org>
Subject: Re: [REGRESSION] Two issues that prevent process accounting (taskstats) from working correctly
Date: Mon, 06 Feb 2017 11:39:04 +0100
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Am Montag, 19. Dezember 2016, 18:25:49 CET schrieb Peter Zijlstra:
> On Mon, Dec 19, 2016 at 01:06:00PM +0100, Martin Steigerwald wrote:
> > 2) When using the NETLINK inface, the command TASKSTATS_CMD_GET
> > consequently returns -EINVAL.
> > 
> > The code that is used by the atopacctd daemon is based on the demo code
> > 'getdelays.c' that can be found in the kernel source code tree
> > (..../linux/Documentation/accounting/getdelays.c). Also this 'getdelays'
> > program does not work any more (also -EINVAL on the same call)
> > with the newer kernels. I really spent a lot of time on this issue to
> > get the code running (there are many places in the kernel code where
> > -EINVAL for this call can be given), but I did not succeed. It is really
> > an incompatibility introduced by the kernel code.
> > It would be nice if the kernel maintainers provide a working version of
> > the getdelays program in the kernel source tree.
> > 
> > I only experience this problem on Debian8 with a 4.8 kernel (virtual
> > machine with 4 cores).
> > On CentOS7 with a 4.8 kernel it works fine (physical machine with 4
> > cores).
> > 
> > I will anyhow adapt atopacctd for this issue that it detects and logs
> > the -EINVAL and terminates.
> > The current version of atopacctd keeps running which is not useful at all.
> > 
> > 
> > I reported this as:
> > 
> > Bug 190711 - Process accounting: Using the NETLINK inface, the command
> > TASKSTATS_CMD_GET returns -EINVAL
> > 
> > https://bugzilla.kernel.org/show_bug.cgi?id=190711
> 
> Ben Hutchings reports:
> 
> "It looks like the taskstats bug was introduced by 513e3d2d11c9 as that
> means cpumask_parse() may not initialise as many bits as
> cpumask_subset() compares"

Thank you.

Okay, any conclusion out of this? Any feedback from the maintainers of this 
code?

Thank you,