linux-kernel - Re: [PATCH Resend 1/3] sched: fix nr_busy

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>] [day] [month] [year] [list]

Date:	Fri, 25 Jan 2013 15:05:19 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Vincent Guittot <vincent.guittot@...aro.org>
Cc:	linaro-dev@...ts.linaro.org, linux-kernel@...r.kernel.org,
	ccross@...roid.com, peterz@...radead.org, mingo@...nel.org
Subject: Re: [PATCH Resend 1/3] sched: fix nr_busy_cpus with coupled cpuidle

2013/1/25 Vincent Guittot <vincent.guittot@...aro.org>:
>
> Le 25 janv. 2013 13:00, "Frederic Weisbecker" <fweisbec@...il.com> a écrit :
>
>
>>
>> 2013/1/25 Vincent Guittot <vincent.guittot@...aro.org>:
>> > This sequence is not the right one
>> >
>> >> I'm going to look for the saved trace to check the sequence above
>> >
>> > I haven't been able to reproduce the bug that this patch was supposed to
>> > solved. The patch 2 and 3 seem enough to fix the nr_busy_cpus field. I
>> > will
>> > continue to try to reproduce it but it seems that it was a side effect
>> > of
>> > the 2 others fixes of the series
>>
>> Ok. I just checked again as well and I can't find a scenario where
>> this can happen. If you find it out or trigger the bug again, don't
>> hesitate to resend this patch.
>
> Ok. I'm going to update the patch serie without this patch

Actually your second patch may cause this, as it clears the NOHZ_IDLE
flag on CPUs that are idle on boot and which could stay that way for a
while. And your second patch is spotting something serious. I'll reply
on it after more thoughts.
--
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/