kern/41157: KASSERT(vp->v_iflag & VI_ONWORKLST) failed on 5.0

[Manuel Bouyer <Manuel.Bouyer%lip6.fr@localhost>]

>Number:         41157
>Category:       kern
>Synopsis:       KASSERT(vp->v_iflag & VI_ONWORKLST) failed on 5.0
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 06 06:35:00 +0000 2009
>Originator:     Manuel Bouyer
>Release:        NetBSD 5.0_RC3
>Organization:
>Environment:
System: NetBSD horn 5.0_RC3 NetBSD 5.0_RC3 (DISCODEBUG) #34: Sun Apr 5 21:37:10 
MEST 2009 bouyer@disco:/home/bouyer/src-5/src/sys/arch/i386/compile/DISCODEBUG 
i386
Architecture: i386
Machine: i386
>Description:
        While testing the NFS server code (it had 2 linux clients running
        both a bonniee++ and a build.sh -j16), it paniced with:
panic: kernel debugging assertion "(vp->v_iflag & VI_ONWORKLST)" failed: file 
"../../../../miscfs/genfs/genfs_io.c", line 1017
fatal breakpoint trap in supervisor mode
trap type 1 code 0 eip c03fb65c cs 8 eflags 246 cr2 cdb80000 ilevel 0
Stopped in pid 0.50 (system) at netbsd:breakpoint+0x4:  popl    %ebp
db{1}> tr
breakpoint(c0652a42,ce36ea88,c2d08800,c03326d2,c2af499a,0,c03b02ad,1,41,41) 
atnetbsd:breakpoint+0x4
panic(c069b46c,c0625521,c065969e,c0659744,3f9,1,ce36ebfc,c03b7a4b,c0625521,c0659744)
 at netbsd:panic+0x1b0
__kernassert(c0625521,c0659744,3f9,c065969e,6,0,c0360204,ce36eba4,8,8) at 
netbsd:__kernassert+0x39
genfs_do_putpages(d11a78b0,6cbb000,0,6cbc000,0,9,0,c035d8e5,c071f30c,c071b4c4) 
at netbsd:genfs_do_putpages+0x10eb
genfs_putpages(ce36ec4c,ce3435c0,0,c071b4c4,0,d11a78b0,c05258a0,d11a78b0,6cbb000,0)
 at netbsd:genfs_putpages+0x3d
VOP_PUTPAGES(d11a78b0,6cbb000,0,6cbc000,0,9,2aa,1e8,0,1000000) at 
netbsd:VOP_PUTPAGES+0x7f
uvm_pageout(ce3435c0,0,c01002a7,0,c01002a7,0,0,0,0,0) at 
netbsd:uvm_pageout+0x419
db{1}> mach cpu 0
using CPU 0
db{1}> tr
__cpu_simple_lock(c3d81db0,0,3,8,c3d81db0,c06aec00,cd13fd40,c039db8a,3,c0100008)
 at netbsd:__cpu_simple_lock+0x17
biodone2(3,c0100008,3,cbf87780,cbf7b250,cbf7b004,cd13fd80,c0343e2d,0,cbf80010) 
at netbsd:biodone2+0x99
biointr(0,cbf80010,cbf80030,cd130010,10,0,f87c80,c2da5a80,0,cd13fda0) at 
netbsd:biointr+0x3a
softint_dispatch(ce434a00,3,0,0,0,0,cd13fd90,cd13fca4,c2da5780,0) at 
netbsd:softint_dispatch+0xcd
DDB lost frame for netbsd:Xsoftintr+0x3d, trying 0xcd13fd88
Xsoftintr() at netbsd:Xsoftintr+0x3d
--- interrupt ---
uvm_fault(0xc071d100, 0, 1) -> 0xe
fatal page fault in supervisor mode
trap type 6 code 0 eip c03fdabf cs 8 eflags 10202 cr2 3b ilevel 8
kernel: supervisor trap page fault, code=0
Faulted in DDB; continuing...

        I have a kernel core dump and netbsd.gdb

>How-To-Repeat:
        build a kernel with DIAGNOSTIC, run NFS server and generate some
        load
>Fix: