UPDATE 799238 - SMP lockup between ramdisk & XFS

[pv@xxxxxxxxxxxxx (dxm@xxxxxxxxxxxx)]

View Incident: 
http://co-op.engr.sgi.com/BugWorks/code/bwxquery.cgi?search=Search&wlong=1&view_type=Bug&wi=799238

 Status : open                         Priority : 2                         
 Assigned Engineer : nb                Submitter : dxm                      
 Opened Date : 08/15/00               *Modified User : dxm                  
*Modified User Domain : engr          *Description :
OK, so this one is repeatable now, and it looks like an
interraction between the ramdisk driver and XFS.

        2 way SMP 1400 with 1Gb memory, 
        SCSI disk. 
        t-o-t kernel, kio _not_ enabled.
        
setup:

        mkfs -t xfs -f /dev/sdc5

.....


==========================
ADDITIONAL INFORMATION (UPDATE)
From: dxm@engr (BugWorks)
Date: Aug 16 2000 10:25:32PM
==========================

CPU A:

sys_sync
        sync_buffers 
                takes lru_list_lock
                interrupt -> sym53c8xx_intr
                        takes io_request_lock

CPU B:

sys_open
        generic_unplug_device
                takes io_request_lock
                insert_into_queues
                        takes lru_list_lock

equals: race condition (yay!) And I can't see where XFS
is involved, which kind of suggests it is, but I haven't
been able to repeat this one without using, so go figure.