3.5.0-rc5: BUG: soft lockup - CPU#0 stuck for 22s

[Benjamin Herrenschmidt]

On Sun, 2012-07-01 at 00:18 -0700, Christian Kujau wrote:
> Hi,
> 
> while trying to upgrade from 3.4.0 to 3.5.0-rc5 on this Powerbook G4 
> (powerpc 32 bit), this happens during booting:
> 
> --------------
> usb 2-1: new full-speed USB device number 4 using ohci_hcd
> SCSI subsystem initialized
> scsi0 : SBP-2 IEEE-1394
> scsi1 : SBP-2 IEEE-1394
> firewire_sbp2 fw1.0: logged in to LUN 0000 (0 retries)
> scsi 0:0:0:0: Direct-Access     Ext Hard  Disk            PQ: 0 ANSI: 4

Interesting... I observed something roughly similar on a dual G4
the other day associated with a 30s to 1mn pause during boot. RCU
was complaining loudly.

In my case, it did continue booting normally, is that the case for you ?

Also if I compile the kernel without CONFIG_SMP, it did go away as well,
do you observe that too ?

I don't have a spare cycle to investigate this problem this week I'm
afraid, it might help if you could try a bisection though.

Cheers,
Ben.