Date: Wed, 14 Jun 2017 15:35:59 -0700
From: Guenter Roeck <linux@roeck-us.net>
To: Frank Rowand <frowand.list@gmail.com>
Cc: Frank Rowand <frank.rowand@sony.com>, linux-kernel@vger.kernel.org,
        Rob Herring <robh@kernel.org>
Subject: Re: Qemu crashes in -next due to 'of: remove *phandle properties
 from expanded device tree'
Message-ID: <20170614223559.GA19172@roeck-us.net>
References: <20170614192638.GA15210@roeck-us.net>
 <5941AB4E.3070804@gmail.com>
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On Wed, Jun 14, 2017 at 02:31:58PM -0700, Frank Rowand wrote:
> Hi Guenter,
> 
> Thanks for reporting this.
> 
> 
> On 06/14/17 12:26, Guenter Roeck wrote:
> > Hi Frank,
> > 
> > your commit 'of: remove *phandle properties from expanded device tree' in
> > -next causes several of my ppc qemu tests to crash. Looking into qemu, it
> > sets "linux,phandle" properties for the mpic and for other devices.
> > 
> > The crashes are along the line of
> > 
> > ------------[ cut here ]------------
> > kernel BUG at arch/powerpc/platforms/85xx/corenet_generic.c:50!
> > Oops: Exception in kernel mode, sig: 5 [#1]
> > SMP NR_CPUS=32 
> > NUMA 
> > CoreNet Generic
> > Modules linked in:
> > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.12.0-rc5-next-20170614 #1
> > task: c000000000ad8cc0 task.stack: c000000000bec000
> > NIP: c000000000a8ca7c LR: c000000000a8ca6c CTR: c000000000a8ca20
> > REGS: c000000000befb90 TRAP: 0700   Not tainted  (4.12.0-rc5-next-20170614)
> > MSR: 0000000080021000 <CE,ME>
> >   CR: 22000042  XER: 00000000
> >   SOFTE: 0 
> >   GPR00: c000000000a8ca6c c000000000befe10 c000000000befa00 0000000000000000 
> >   GPR04: 0000000000000000 c000000000ac8458 c000000000ac8438 c000000000830658 
> >   GPR08: 0000000000000001 0000000000000001 0000000000000000 0000000000009531 
> >   GPR12: 0000000022000022 c00000003fff1000 0000000000000000 0000000000000000 
> >   GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
> >   GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
> >   GPR24: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
> >   GPR28: c000000000000300 c00000003fff2cc0 c000000000ac06e0 c000000000ac06e0 
> >   NIP [c000000000a8ca7c] .corenet_gen_pic_init+0x5c/0x90
> >   LR [c000000000a8ca6c] .corenet_gen_pic_init+0x4c/0x90
> >   Call Trace:
> >   [c000000000befe10] [c000000000a8ca6c] .corenet_gen_pic_init+0x4c/0x90
> >   (unreliable)
> >   [c000000000befe80] [c000000000a832f8] .init_IRQ+0x34/0x4c
> >   [c000000000befef0] [c000000000a7fc88] .start_kernel+0x2fc/0x500
> >   [c000000000beff90] [c000000000000554] start_here_common+0x1c/0x48
> >   Instruction dump:
> >   e8aa0068 39088268 39407002 38600000 7fa54800 39205002 7caa4f9e 4bffe9e9 
> >   60000000 2c230000 7d200026 55291ffe <0b090000> 4bfff335 60000000 3ca2ffdd 
> >   random: 0x600000003d220004 get_random_bytes called with crng_init=0
> >   ---[ end trace 0000000000000000 ]---
> > 
> > and are caused by the kernel not finding the mpic node anymore.
> > 
> > Any idea how to solve the problem ?
> 
> The BUG() is triggered if mpic_alloc() returns NULL.
> 
Yes, I got that far as well ...

> I looked through mpic_alloc(), and the functions that it calls, and nothing
> is jumping out as being related to phandles.
> 
> Can you add some printks to mpic_alloc() to determine what problem is
> causing it to return NULL?
> 
I'll try later tonight.

> Can you also include the console messages before the "[ cut here ]" line?
> 
http://kerneltests.org/builders

Check qemu test results in the 'next' column. ppc and ppc64 show related console
messages.

Guenter