Re: [4/5] 2.6.21-rc5: known regressions

[Ingo Molnar]

* Adrian Bunk <bunk@xxxxxxxxx> wrote:

> Subject    : second suspend to disk in a row results in an oops  (MSI)
> References : http://lkml.org/lkml/2007/3/17/43
>              http://lkml.org/lkml/2007/3/22/150
>              http://lkml.org/lkml/2007/3/26/205
>              http://lkml.org/lkml/2007/3/26/76
> Submitter  : Thomas Meyer <thomas@xxxxxxxx>
>              Frédéric Riss <frederic.riss@xxxxxxxxx>
>              Marcus Better <marcus@xxxxxxxxx>
> Handled-By : Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> Patch      : http://lkml.org/lkml/2007/3/24/136
> Status     : patch was suggested

i can reproduce a crash on the second suspend-to-ram, on a T60. I get a 
crash here:

 #ifdef CONFIG_PM
 static void __pci_restore_msi_state(struct pci_dev *dev)
 {
         int pos;
         u16 control;
         struct msi_desc *entry;

         if (!dev->msi_enabled)
                 return;

         entry = get_irq_msi(dev->irq);
         pos = entry->msi_attrib.pos; <-------- crash on NULL dereference


i.e. 'entry' is NULL after get_irq_msi(). (i can see the crash only on 
the VGA screen so no dump of it available. Can write down more info if  
it's helpful.)

I have tried Eric's patch above but now i always get a hang after 
"system 00:00: resuming", already upon the first suspend-resume. Not 
even the NMI watchdog can get the system out of that hang.

	Ingo
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