Re: applesmc oops in 3.10/3.11

[Guenter Roeck]

On 10/01/2013 08:55 PM, Chris Murphy wrote:
> On Oct 1, 2013, at 9:51 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> > On Tue, Oct 01, 2013 at 07:09:26PM -0600, Chris Murphy wrote:
> > > On Oct 1, 2013, at 10:24 AM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> > >
> > > > On Tue, Oct 01, 2013 at 09:33:13AM -0600, Chris Murphy wrote:
> > > > > On Oct 1, 2013, at 9:19 AM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> > > > >
> > > > > > On Tue, Oct 01, 2013 at 12:55:26PM +0200, Henrik Rydberg wrote:
> > > > > > > > > Warning message triggered with 3.12.0-0.rc3.git0.1.fc21.x86_64.
> > > > > > > > >
> > > > > > > > > [   10.886016] applesmc: key count changed from 261 to 1174405121
> > > > > > > >
> > > > > > > > Explains the crash, but the new key count is very wrong. 1174405121 = 0x46000001.
> > > > > > > > Which I guess explains the subsequent memory allocation error in the log.
> > > > > > > >
> > > > > > > > Henrik, any idea what might be going on ? Is it possible that the previous
> > > > > > > > command failure leaves some state machine in a bad state ?
> > > > > > >
> > > > > > > I seem to recall a report on another similar state problem on newer
> > > > > > > machines, so maybe, yes. Older machines seem fine, I have never
> > > > > > > encountered the problem myself. Here is a patch to test that
> > > > > > > theory. It has been tested to be pretty harmless on two different
> > > > > > > generations.
> > > > > > >
> > > > > > > I really really do not want to add an 'if (value is insane)' check ;-)
> > > > > > Chris,
> > > > > >
> > > > > > any chance you can load this patch on an affected machine so we can get
> > > > > > test feedback ? This one is too experimental to submit upstream without
> > > > > > knowing that it really fixes the problem.
> > > > >
> > > > > Yes. What kernel.org source version should I apply it against? I'd use the non-debug config file from an equivalent version Fedora kernel, unless asked otherwise. And also should I test it on other vintages? I have here MBP4,1(2008); MBP8,2(2011), and MBP10,2(2012).
> > > > Only requirement is that it also includes the previous patch, so it would be
> > > > optimal if you can apply it on top of the previous image.
> > >
> > > Patch added on top of 3.12.0-0.rc3.git0.1.fc20.x86_64 and built. But after ~dozen reboots, I'm not triggering the problem. The only items in dmesg with smc in it:
> > >
> > > [   13.799819] applesmc: key=261 fan=2 temp=14 index=14 acc=1 lux=2 kbd=1
> > > [   13.833402] input: applesmc as /devices/platform/applesmc.768/input/input10
> >
> > Hi Chris,
> >
> > That only means that you did not hit the problem. There may be some secondary
> > trigger (cold boot ? coffee on the cpu ?).
> >
> > One thing I have seen in all logs is the earlier "send_byte fail" message, so
> > I think that is a pre-requisite.
>
> I have no idea how to trigger it. I have tried cold and warm boots. Boots between linux and OS X to linux. *shrug* I'll keep trying as I'm doing other testing, maybe I'll stumble onto it.

I am sure you didn't pour coffee onto the CPU yet :)

Basic rule of testing: You'll only hit the problem again after you are convinced
that it was magically fixed by a completely unrelated change.

Cheers,
Guenter

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