Re: 2.6.20: reproducible hard lockup with RAID-5 resync

[Corey Hickey <bugfood-ml@fatooh.org>]

Neil Brown wrote:
> On Thursday February 15, bugfood-ml@fatooh.org wrote:
>> I think I have found an easily-reproducible bug in Linux 2.6.20. I have
>> already applied the "Fix various bugs with aligned reads in RAID5"
>> patch, and that had no effect. It appears to be related to the resync
>> process, and makes the system lock up, hard.
> 
> I'm guessing that the problem is at a lower level than raid.
> What IDE/SATA controllers do you have?  Google to see if anyone else
> has had problems with them in 2.6.20.
>> During the lock up, nothing is printed to the console, and the magic
>> SysRQ key has no effect; I have to poke the reset button.
> 
> Sound's like interrupts are disabled, but x86_64 always enables the
> NMI watchdog which should trigger if interrupts are off for too long. 
> 
> Do you have CONFIG_DETECT_SOFTLOCKUP=y in your .config (it is in the
> kernel debugging options menu I think).  If not, setting that would be
> worth a try.
> 
> A raid5 resync across 5 sata drives on a couple of different
> silicon-image controllers doesn't lock up for me.

Wow, thanks for the quick response. I have to go to bed now, but I'll
try to get you that information tomorrow.

Thanks,
Corey