kern/40296: kernel crash at high nfs traffic

[6bone%informatik.uni-leipzig.de@localhost]

>Number:         40296
>Category:       kern
>Synopsis:       kernel crash at high nfs traffic
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Dec 30 16:05:00 +0000 2008
>Originator:     Uwe Toenjes
>Release:        NetBSD 5.0 beta
>Organization:
University of Leipzig
>Environment:
NetBSD 6bone.informatik.uni-leipzig.de 5.0_BETA NetBSD 5.0_BETA (MYCONF) #0: 
Mon Dec 29 14:12:10 CET 2008  
root%6bone.informatik.uni-leipzig.de@localhost:/usr/obj/sys/arch/amd64/compile/MYCONF
 amd64
>Description:
After some time with high nfs load the kernel crashes with:


fatal page fault in supervisor mode                                             
trap type 6 code 0 rip ffffffff8035713f cs 8 rflags 10246 cr2  2b93ae18c cpl 4 0
kernel: page fault trap, code=0                                                 
Stopped in pid 0.5 (system) at  netbsd:nfs_timer+0x1af: movl    netbsd:proct(%ri
p,%rax,4),%eax                                                                  
db{0}> trace                                                                    
nfs_timer() at netbsd:nfs_timer+0x1af                                           
callout_softclock() at netbsd:callout_softclock+0x21b                           
softint_dispatch() at netbsd:softint_dispatch+0xd3                              
DDB lost frame for netbsd:Xsoftintr+0x50, trying 0xffff8000693fcd70             
Xsoftintr() at netbsd:Xsoftintr+0x50                                            
--- interrupt ---                                                               
0:                                                                              
>How-To-Repeat:
at my system it is repeatable by extracting a large tar file (some gigabyte) 
including a lot of small files at an nfs-mounted filesystem
>Fix: