[Stgt-devel] disk kicked out of RAID -> tgtd segmentation fault

[Tomasz Chmielewski]

ronnie sahlberg schrieb:
> Hi Tomasz,
> 
> I could not get that configuration to work.
> 
> Can you please provide more detailed instructions exactly how to set
> up hosts A B and C
> so I can try to reproduce it.
> 
> Please provide the exact commandline for each and every command I need
> to run on the three hosts and Ill try to
> reproduce it under gdb.

A faulty RAID is just one way to crash tgtd.

A simpler one is to just block the traffic between the target and the 
initiator - just login to the target, make sure there is some iSCSI 
traffic between the target and the initiator, then block incoming iSCSI 
traffic on the initiator with:

initiator# iptables -I INPUT -s <target IP> -p tcp --sport 3260 -j DROP


After a while, you will see that only one tgtd process is running, 
whereas the second has crashed.


I'm not sure if the two ways of causing tgtd crash are related. If they 
are, it might be some timing issue?

Failing RAID may cause that tgtd is not able to access the disk for 
several seconds, or about a minute. Failing RAID is also likely.

Blocking incoming iSCSI traffic on the initiator, although less likely 
in the real world, also confuses tgtd to the point where it crashes.

The above is valid with tgt-20080527, I'm just about to try tgt-20080629.


-- 
Tomasz Chmielewski
http://wpkg.org