From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Borleis Subject: Re: PowerPC: massive "scheduling while atomic" reports Date: Tue, 15 Sep 2015 10:53:15 +0200 Message-ID: <201509151053.16563.jbe@pengutronix.de> References: <201509101106.56931.jbe@pengutronix.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "linux-rt-users" , LKML To: Thomas Gleixner Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:56434 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752670AbbIOIxD convert rfc822-to-8bit (ORCPT ); Tue, 15 Sep 2015 04:53:03 -0400 In-Reply-To: Content-Disposition: inline Sender: linux-rt-users-owner@vger.kernel.org List-ID: 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 b= unch=20 off "scheduling while atomic" reports and we re-booted it and it was si= lent.=20 That's why we thought it might be a race instead of a systematic failur= e. > [...] > 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=20 and were lost in the code. Seems you are in a pole position due to your= =20 experience with the RT preempt code. The good news: I tried your suggested change on my system and reboot it= again=20 and again since an hour now and no more "scheduling while atomic" repor= ts=20 occur. \o/ Thank you very much Juergen --=20 Pengutronix e.K. =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0| Juergen Borleis =A0 =A0 =A0 =A0 =A0 =A0 | Industrial Linux Solutions =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0| htt= p://www.pengutronix.de/ =A0| -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html