Subject: Is 1.6 NFS buggy?
To: None <current-users@netbsd.org>
From: None <kpneal@pobox.com>
List: current-users
Date: 11/29/2002 23:15:52
I've got a crash on my Alpha running 1.6. The crash is in NFS and I'm
wondering if anyone else has seen it. 

Hand-written traceback:

nfs_reclaim+0x80
vclean+0x258
vgonel+0x70
getnewvnode+0x310
ffs_vget+0x8c
vfs_lookup+0x1028
lookup+0x4bc
namei+0x4c8
sys__lstat13+0x58
syscall_plain+0x154
syscall 280

The offending line of code:

/usr/src/sys16/nfs/nfs_node.c:285
 93c:   00 00 6a a0     ldl     t2,0(s1)
 940:   83 16 61 48     srl     t2,0x8,t2        ********* Blamo!
 944:   18 00 60 e0     blbc    t2,9a8 <nfs_reclaim+0xe8>
 948:   88 00 49 a4     ldq     t1,136(s0)
 94c:   16 00 40 e4     beq     t1,9a8 <nfs_reclaim+0xe8>
/usr/src/sys16/nfs/nfs_node.c:286

        /*
         * For nqnfs, take it off the timer queue as required.
         */
--->    if ((nmp->nm_flag & NFSMNT_NQNFS) && np->n_timer.cqe_next != 0) {
                CIRCLEQ_REMOVE(&nmp->nm_timerhead, np, n_timer);
        }


The result is this nastyness:

CPU 0: fatal kernel trap:

CPU 0    trap entry = 0x4 (unaligned access fault)
CPU 0    a0         = 0xdeadbeefdeadbeef
CPU 0    a1         = 0x28
CPU 0    a2         = 0x3
CPU 0    pc         = 0xfffffc0000351e20
CPU 0    ra         = 0xfffffc0000448f38
CPU 0    pv         = 0xfffffc0000351da0
CPU 0    curproc    = 0xfffffc0000a37448
CPU 0        pid = 17495, comm = find

panic: trap
tlp0: receive ring overrun
tlp1: receive ring overrun
syncing disks... panic: lockmgr: locking against myself

dumping to dev 8,9 offset 298595
dump 48 47 46 45 44 43 42 41 40 39 38 37 36 35 
unexpected machine check:

    mces    = 0x1
    vector  = 0x670
    param   = 0xfffffc0000006048
    pc      = 0xfffffc0000307be8
    ra      = 0xfffffc0000307bd4
    code    = 0x100000084
    curproc = 0xfffffc0000a37448
        pid = 17495, comm = find

panic: machine check

dumping to dev 8,9 offset 298595
dump device not ready

-- 
Kevin P. Neal                                http://www.pobox.com/~kpn/

"It sounded pretty good, but it's hard to tell how it will work out
in practice." -- Dennis Ritchie, ~1977, "Summary of a DEC 32-bit machine"