linux-kernel - Re: Runtime PM causes oops on next-20151015

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Date:	Thu, 15 Oct 2015 23:24:21 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Thierry Reding <thierry.reding@...il.com>
Cc:	Michael Ellerman <mpe@...erman.id.au>,
	Wonhong Kwon <wonhong.kwon@....com>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	linux-next@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: Runtime PM causes oops on next-20151015

On Thursday, October 15, 2015 03:26:55 PM Thierry Reding wrote:
> 
> --pf9I7BMVVzbSWLtt
> Content-Type: text/plain; charset=us-ascii
> Content-Disposition: inline
> Content-Transfer-Encoding: quoted-printable
> 
> On Thu, Oct 15, 2015 at 09:04:54PM +1100, Michael Ellerman wrote:
> > On Thu, 2015-10-15 at 11:22 +0200, Thierry Reding wrote:
> > > Hi Rafael, Wonhong,
> > >=20
> > > Todays linux-next breaks rather spectacularly for drivers using runtime
> > > PM. The culprit seems to be this commit:
> > >=20
> > > 	commit 7d24068e144adc03b805806645d732cf79488717
> > > 	Author: Wonhong Kwon <wonhongkwon@...il.com>
> > > 	Date:   Tue Oct 6 10:10:20 2015 +0900
> > >=20
> > > 	    PM / hibernate: Move pm_init/pm_disk_init to late_initcall_sync
> > >=20
> > > 	    pm_init is being invoked by core_initcall and hibernate_image_size=
> _init
> > > 	    calculates preferred image size (image_size) based on total pages
> > > 	    (totalram_pages). This totalram_pages can be modified during vario=
> us
> > > 	    initcall-s phase and this can cause miscalculated image_size.
> > >=20
> > > 	    For example, when CMA is being used, init_cma_reserved_pageblock t=
> ries
> > > 	    to change the totalram_pages and this job is done during core_init=
> call.
> > > 	    In order words, the totalram_pages doesn't take CMA reserved pages=
>  into
> > > 	    account when image_size is calculated and it can be too small.
> > >=20
> > > 	    Move pm_init and pm_disk_init to late_initcall_sync so that it hap=
> pens
> > > 	    after all other initcall-s change the totalram_pages.
> > >=20
> > > 	    Reported-by: Sangseok Lee <sangseok.lee@....com>
> > > 	    Signed-off-by: Wonhong Kwon <wonhong.kwon@....com>
> > > 	    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > >=20
> >=20
> > I'm seeing one too on powerpc:
> >=20
> > Unable to handle kernel paging request for data at address 0x00000030
> > Faulting instruction address: 0xc0000000002e4094
> > Oops: Kernel access of bad area, sig: 11 [#1]
> > SMP NR_CPUS=3D2048 NUMA pSeries
> > Modules linked in:
> > CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.3.0-rc5-next-20151015-50217-g=
> e2be40d-dirty #37
> > task: c0000001fefc0000 ti: c0000001fb000000 task.ti: c0000001fb000000
> > NIP: c0000000002e4094 LR: c000000000c79dd4 CTR: c000000000c79d90
> > REGS: c0000001fb003900 TRAP: 0300   Not tainted  (4.3.0-rc5-next-20151015=
> -50217-ge2be40d-dirty)
> > MSR: 8000000100009032 <SF,EE,ME,IR,DR,RI>  CR: 28000882  XER: 20000000
> > CFAR: c0000000000d117c DAR: 0000000000000030 DSISR: 40000000 SOFTE: 1=20
> > GPR00: c00000000000b074 c0000001fb003b80 c000000000e93800 000000000000000=
> 0=20
> > GPR04: c000000000d15c80 0000000000000000 00000001ff150000 000000000000002=
> 6=20
> > GPR08: c000000000d0f748 c000000000f41a10 c000000000d0f8e8 c000000000abc59=
> d=20
> > GPR12: c000000000b42400 c00000000fdc1680 c00000000000b960 000000000000000=
> 0=20
> > GPR16: 0000000000000000 0000000000000000 0000000000000000 000000000000000=
> 0=20
> > GPR20: 0000000000000000 0000000000000000 0000000000000000 000000000000000=
> 0=20
> > GPR24: 0000000000000000 c000000000de0360 c000000000c45d28 000000000000000=
> 0=20
> > GPR28: c000000000deca80 c000000000d103c0 c0000001fbc905c0 c000000000d103c=
> 0=20
> > NIP [c0000000002e4094] .sysfs_create_file_ns+0x4/0x50
> > LR [c000000000c79dd4] .__machine_initcall_pseries_apo_pm_init+0x44/0x60
> > Call Trace:
> > [c0000001fb003b80] [c0000000004852cc] .kasprintf+0x2c/0x40 (unreliable)
> > [c0000001fb003bf0] [c00000000000b074] .do_one_initcall+0xc4/0x250
> > [c0000001fb003ce0] [c000000000c64560] .kernel_init_freeable+0x268/0x348
> > [c0000001fb003db0] [c00000000000b97c] .kernel_init+0x1c/0x140
> > [c0000001fb003e30] [c0000000000095ac] .ret_from_kernel_thread+0x58/0xac
> > Instruction dump:
> > 419e001c 3ce2ffa8 38e7be60 4bfffea4 3ce2ffa8 38e7bea8 4bfffe9c 3ce2ffa8=
> =20
> > 38e7bea8 4bfffe8c 60000000 2c230000 <e8630030> 41820028 2fa30000 419e0020=
> =20
> > ---[ end trace d2a742ce359651dd ]---
> >=20
> > Kernel panic - not syncing: Attempted to kill init! exitcode=3D0x0000000b
> >=20
> >=20
> > Which starts at:
> >=20
> >   static int __init apo_pm_init(void)
> >   {
> >   	return (sysfs_create_file(power_kobj, &auto_poweron_attr.attr));
> >   }
> >   machine_device_initcall(pseries, apo_pm_init);
> >=20
> > And seems to be caused by power_kobj being NULL:
> >=20
> >   0:mon> d $power_kobj
> >   c000000000f41a10 0000000000000000 0000000000000000  |................|
> 
> Yes, power_kobj is one of the other objects created by pm_init() and
> which, evidently, needs to be available much earlier than late_initcall.
> The patch below works for me, though I don't use hibernate on this
> machine, so that part is untested.

Sorry about the breakage and thanks for identifying the problematic commit.

I've dropped that commit from my tree.

Thanks,
Rafael

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