Re: spinlock lockup on CPU#0

[Justin Mattock]

On Mon, Apr 28, 2008 at 8:38 PM, Venki Pallipadi
<venkatesh.pallipadi@xxxxxxxxx> wrote:
> On Sat, Apr 26, 2008 at 09:48:55PM +0000, Justin Mattock wrote:
>  > On Sat, Apr 26, 2008 at 9:06 PM, Bob Copeland <me@xxxxxxxxxxxxxxx> wrote:
>  > > On Sat, Apr 26, 2008 at 3:14 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
>  > >  >  > Can you add this please, see if it triggers?
>  > >  >
>  > >  >  there's fixes pending in this area. The main fix would be the one below.
>  > >  >
>  > >  >         Ingo
>  > >  >
>  > >  >  ---------------->
>  > >  >  Subject: idle (arch, acpi and apm) and lockdep
>  > >
>  > >  FWIW, I was seeing the same lockdep trace with eventual hangs, and
>  > >  this patch (applied with some fuzz) fixed the problem.
>  > >
>  > >  --
>  > >  Bob Copeland %% www.bobcopeland.com
>  > >
>  >
>  > Just out of curiosity I put the kernel back to it's original state,
>  > were the freezing occurs, then booted with nohz=off, then added
>  > WARN_ON(!irqs_disabled()); to sched.c only to the kernel, no other
>  > patches, upon rebooting
>  > I received different results: The screen from what I could tell was
>  > spitting out the spinlock messages, but instead of printing that out,
>  > and going on to the next task it just keep't printing, from what I
>  > could tell something with ehci, uhci, agpgart, ieee1394 etc... too
>  > fast to really make anything out, the numbers on the left side keept
>  > moving upward, the fans started hauling ass, I waitied a few minuetes
>  > hopeing this would stop
>  > so I can grab dmesg, but it would'nt. is there a way to use the boot
>  > param to write date to a file? so I could capture this event.
>  > regards
>  >
>
>  OK. Hunted this bug down to
>  commit 3b22ec7b13cb31e0d87fbc0aabe14caaaad309e8
>
>  which for some reason enables interrupt in mwait_idle_with_hints(), which
>  eventually causes interrupts to be enabled in acpi idle call, resulting in
>  sched_clock_idle_wakeup_event() with interrupts enabled. This bug
>  was only in x86 32 bit version.
>
>  Peter's patch below which is already in git fixes this. So we don't need any
>  additional fixes here...
>
>  Thanks,
>  Venki
>
>

Alright, I was concerned about having additional fixes.
regards;

-- 
Justin P. Mattock
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