Subject: kern/26878: FFSv2 + softdep = livelock (no free ram)
To: None <gnats-bugs@gnats.NetBSD.org>
From: Richard Earnshaw <rearnsha@buzzard.freeserve.co.uk>
List: netbsd-bugs
Date: 09/07/2004 20:43:12
>Number:         26878
>Category:       kern
>Synopsis:       FFSv2 + softdep = livelock (no free ram)
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Sep 07 23:33:00 UTC 2004
>Closed-Date:
>Last-Modified:
>Originator:     Richard Earnshaw
>Release:        NetBSD 2.0_BETA
>Organization:
None.
	
>Environment:
	
	
System: NetBSD osprey.buzzard.freeserve.co.uk 2.0_BETA NetBSD 2.0_BETA (OSPREY) #0: Thu Aug 5 20:31:21 BST 2004 rearnsha@merlin.buzzard.freeserve.co.uk:/work/rearnsha/netbsd/build/cats/src/sys/arch/cats/compile/OSPREY cats
	Physical RAM 128M.  HDD: 80G Maxtor running in UDMA-1 mode.
Architecture: arm
Machine: cats
>Description:
	creating a FFSv2 filesystem and then mounting it with soft 
	dependencies can lead to the situation where the kernel runs out of
	free memory if there is heavy disk activity (eg untarring a large
	amount of data).  The system isn't truly dead (top continues to
	run), but shows that there is only ~4k (1 page) of memory on the
	free list.  However, no new processes can be started and it's 
	impossible to kill any existing ones.
	
>How-To-Repeat:
	As above.
	
>Fix:
	No idea.  Probably should ignore softdep flag if FFSv2 mode for now.
	
>Release-Note:
>Audit-Trail:
>Unformatted: