From: Juergen Borleis <jbe@pengutronix.de>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "linux-rt-users" <linux-rt-users@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: PowerPC: massive "scheduling while atomic" reports
Date: Tue, 15 Sep 2015 10:53:15 +0200 [thread overview]
Message-ID: <201509151053.16563.jbe@pengutronix.de> (raw)
In-Reply-To: <alpine.DEB.2.11.1509142235440.3971@nanos>
Hi Thomas,
On Tuesday 15 September 2015 00:05:31 Thomas Gleixner wrote:
> Please CC lkml on bug reports for RT.
Okay.
> > When running the system at least every other boot this kernel spits out
> > massive "scheduling while atomic" reports.
>
> I doubt that this only happens on every other boot. This is a
> systematic failure.
That was one of the confusing things: we booted the machine and got a bunch
off "scheduling while atomic" reports and we re-booted it and it was silent.
That's why we thought it might be a race instead of a systematic failure.
> [...]
> If you encounter such a 'confusing' problem the next time, then look
> out for commonalities, AKA patterns. 99% of all problems can be
> decoded via patterns. And if you look at the other call chains you'll
> find more instances of those pte_*_lock() calls, which all end up in
> kmap_atomic().
Sounds easy. But we stared with two developers on the code and the bug traces
and were lost in the code. Seems you are in a pole position due to your
experience with the RT preempt code.
The good news: I tried your suggested change on my system and reboot it again
and again since an hour now and no more "scheduling while atomic" reports
occur. \o/
Thank you very much
Juergen
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Pengutronix e.K. | Juergen Borleis |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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next prev parent reply other threads:[~2015-09-15 8:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-10 9:06 PowerPC: massive "scheduling while atomic" reports Juergen Borleis
2015-09-14 22:05 ` Thomas Gleixner
2015-09-15 8:53 ` Juergen Borleis [this message]
2015-09-16 9:48 ` Thomas Gleixner
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