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
| ||
|
Date: Wed, 29 Mar 2017 09:23:57 -0400
From: Luiz Capitulino <lcapitulino@...hat.com>
To: Rik van Riel <riel@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
linux-kernel@...r.kernel.org, linux-rt-users@...r.kernel.org,
Wanpeng Li <kernellwp@...il.com>
Subject: Re: [BUG nohz]: wrong user and system time accounting
On Wed, 29 Mar 2017 09:14:32 -0400
Rik van Riel <riel@...hat.com> wrote:
> > I failed to reproduce with your config. I'm still getting 99%
> > userspace
> > cputime. So I'm wondering if the hogging style plays a role.
> >
> > I run pure user loops:
> >
> > int main(int argc, char **argv)
> > {
> > for (;;);
> > return 0
> > }
> >
> > Does your user program perform syscalls or IOs of some sort?
>
> Luiz's program makes a syscall every millisecond,
> if started with the arguments he gave as his
> reproducer.
There are various reproducers actually. I started off with the simple
loop above, then wrote the attach program and then wrote the one
you're mentioning:
http://people.redhat.com/~lcapitul/real-time/acct-bug.c
All of them reproduce the issue 100% of the time for me.
View attachment "hog.c" of type "text/x-c++src" (999 bytes)
Powered by blists - more mailing lists