From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "regressions@leemhuis.info" <regressions@leemhuis.info>,
        "benh@kernel.crashing.org" <benh@kernel.crashing.org>,
        "Larry.Finger@lwfinger.net" <Larry.Finger@lwfinger.net>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Regression in 4.11 - PowerPC crashes on boot, bisected to
 commit 5657933dbb6e
Thread-Topic: Regression in 4.11 - PowerPC crashes on boot, bisected to
 commit 5657933dbb6e
Thread-Index: AQHSkxTzAk+ZU16MyUOOeUITLE5QRg==
Date: Thu, 2 Mar 2017 05:22:14 +0000
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On Thu, 2017-03-02 at 16:14 +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2017-03-01 at 21:26 -0600, Larry Finger wrote:
> > My Powerbook G4 Aluminum generates a fatal splat early in the boot process, just 
> > after identifying the driver for the disk. Unfortunately, it turns off almost 
> > immediately, thus I cannot report the message. After this bug has been 
> > triggered, the system clock has been reset to Dec. 31, 1969. I assume this is a 
> > side effect of an uncontrolled DMA operation.
> > 
> > This problem has been bisected to commit 5657933dbb6e ("treewide: Move dma_ops 
> > from struct dev_archdata into struct device").
> 
> Side effect of a crash during boot... the PMU gets upset when we crash while
> there's a request in flight, that's probably what is happening.
> 
> As to why that commit is broken, I don't have time to look into it right  now,
> maybe next week of nobody beats me to it.

Hello Ben,

Thanks. I will try to reproduce what has been reported with qemu-ppc on Friday to
double check that it's really commit 5657933dbb6e that is causing this. I reread it
but couldn't find any reason why it works on x86-64 but not on powerpc. BTW, the
following patch is needed on at least s390 but probably also on powerpc to restore
InfiniBand support: http://marc.info/?l=linux-rdma&m=148823342415501&w=2. This is
why I asked for the kernel config.

Bart.