Re: [patch 3/3] clockevents: Fix resume logic - updated version

Andrew Morton
2007-05-13T19:10:16Z

On Sun, 13 May 2007 18:48:07 +0200 Thomas Gleixner <tglx@linutronix.de> wrote:

> On Sun, 2007-05-13 at 10:07 +0200, Thomas Gleixner wrote:
> > > > Can you send me your .config please ?
> > > >
> > >
> > > http://userweb.kernel.org/~akpm/config-sony.txt
> >
> > No luck.
>
> I'm making progress. After fiddling with the config options I get a
> solid lockup of netconsole during boot :(

neat. Sometimes this can be a device driver failure.

> But also lockdep itself is broken on my box, so I would not see warnings
> anyway:
>
> soft-irqs-on + irq-safe-A/21: ok | ok | ok |
> sirq-safe-A => hirqs-on/12: ok | ok |irq event stamp: 472
> hardirqs last enabled at (472): [<c01e8bba>] irqsafe2A_rlock_12+0x94/0xa1
> hardirqs last disabled at (471): [<c0109541>] native_sched_clock+0x55/0xe8
> softirqs last enabled at (468): [<c01e8ba5>] irqsafe2A_rlock_12+0x7f/0xa1
> softirqs last disabled at (464): [<c01e8b31>] irqsafe2A_rlock_12+0xb/0xa1
> FAILED| [<c0104d21>] dump_trace+0x61/0x1e7
> [<c0104ec1>] show_trace_log_lvl+0x1a/0x30
> [<c0105a1b>] show_trace+0x12/0x14
> [<c0105a73>] dump_stack+0x15/0x17
> [<c01e6971>] dotest+0x6b/0x3ce
> [<c01efc1f>] locking_selftest+0x915/0x1a5a
> [<c04a0a0a>] start_kernel+0x1d5/0x2a7
> =======================
>
> .... more of those
>
> -----------------------------------------------------------------
> BUG: 6 unexpected failures (out of 218) - debugging disabled! |
> -----------------------------------------------------------------
>

Yeah, I expect quite a few people will start seeing that. iirc it was
triggered by a couple of changes: a local_irq_save/local_irq_restore in
sched_clock() and a change Jeremy made to the softlockup detector.

There was no reasonable explanation why either of those changes should have
triggered the six failures so I just went ahead with them so we can flush
the real bug out.