rpc.statd hanging

[Simon Kirby <sim@hostway.ca>]

Hello!

Something has been causing rpc.statd to start hanging, which causes
"lockd" to stay in D state on the server, and "lockd: server x not
responding, still trying" on the clients trying to make use of NLM
locking (NFSv3) from this server.

This has happened now with old nfs-utils 1.1.2 and with 1.2.2 (upgraded
after the first time it happened) on the server. It seems to be looping
doing DNS lookups, and never seems to finish. The kernel's lockd keeps
retransmitting requests, but rpc.statd doesn't seem to be finishing
sm_notify_1_svc(), so everything stops.

(gdb) bt
#0  sm_notify_1_svc (argp=0x7fff46ef5430, rqstp=<value optimized out>) at callback.c:107
#1  0x0000000000405a21 in sm_prog_1 (rqstp=0x7fff46ef59b0, transp=0x1b070e0) at sm_inter_svc.c:84
#2  0x00007f674d5fafa1 in svc_getreq_common () from /lib/libc.so.6
#3  0x00007f674d5fb034 in svc_getreqset () from /lib/libc.so.6
#4  0x000000000040527a in my_svc_run () at svc_run.c:129
#5  0x0000000000404cbd in main (argc=1, argv=<value optimized out>) at statd.c:472

sm_notify_1_svc():
   |102             /* okir change: statd doesn't remove the remote host from its
   |103              * internal monitor list when receiving an SM_NOTIFY call from
   |104              * it. Lockd will want to continue monitoring the remote host
   |105              * until it issues an SM_UNMON call.
   |106              */
  >|107             for (lp = rtnl ; lp ; lp = lp->next)
   |108                     if (NL_STATE(lp) != argp->state &&
   |109                         (statd_matchhostname(argp->mon_name, lp->dns_name) ||
   |110                          statd_matchhostname(ip_addr, lp->dns_name))) {
   |111                             NL_STATE(lp) = argp->state;
   |112                             call = nlist_clone(lp);
   |113                             nlist_insert(&notify, call);
   |114                     }
   |115
   |116
   |117             return ((void *) &result);
   |118     }

(gdb) print *rtnl
$11 = {
  mon = {
    mon_id = {
      mon_name = 0x1b07e80 "10.10.52.21",
      my_id = {
        my_name = 0x2a33b30 "nas08",
        my_prog = 100021,
        my_vers = 3,
        my_proc = 16
      }
    }, 
    priv = "\234\bq\000\000\233\001\210"
  },
  port = 0,
  times = 5,
  state = 0,
  dns_name = 0x1e63140 "lsh1008.lsh",
  next = 0x2961480,
  prev = 0x0,
  xid = 0,
  when = 0
}
(gdb) print *lp                                                                      
$12 = {
  mon = {
    mon_id = {
      mon_name = 0x216b390 "10.10.52.28",
      my_id = {
        my_name = 0x216b370 "nas08",
        my_prog = 100021,
        my_vers = 3, 
        my_proc = 16
      }
    }, 
    priv = "005223\a\0338\000\000>\004\210"
  }, 
  port = 0,
  times = 5,
  state = 47, 
  dns_name = 0x216b3b0 "lsh1015.lsh",
  next = 0x216b220,
  prev = 0x216b3e0,
  xid = 0,   
  when = 0
}
(gdb) set $x = rtnl
(gdb) set $count = 0
(gdb) while ($x->next)
 >set $count = $count + 1
 >set $x = $x->next
 >end
(gdb) print $count
$17 = 70916
(gdb) print argp->state
$18 = 89
(gdb) print notify
$19 = (notify_list *) 0x0
(gdb) up
#1  0x0000000000405a21 in sm_prog_1 (rqstp=0x7fff46ef59b0, transp=0x1b070e0) at sm_inter_svc.c:84
(gdb) print rqstp
$21 = (struct svc_req *) 0x7fff46ef59b0
(gdb) print *rqstp
$22 = {
  rq_prog = 100024, 
  rq_vers = 1, 
  rq_proc = 6,    
  rq_cred = {
    oa_flavor = 0, 
    oa_base = 0x7fff46ef54a0 "",
    oa_length = 0
  }, 
  rq_clntcred = 0x7fff46ef57c0 "",
  rq_xprt = 0x1b070e0
}
(gdb) print *transp  
$23 = {
  xp_sock = 7, 
  xp_port = 33188,
  xp_ops = 0x7f674d850840,
  xp_addrlen = 16,
  xp_raddr = {
    sin_family = 2,
    sin_port = 55042,
    sin_addr = {   
      s_addr = 859048458
    }, 
    sin_zero = "\000\000\000\000\000\000\000"
  },   
  xp_verf = {
    oa_flavor = 0,
    oa_base = 0x1b07280 "`",
    oa_length = 0 
  }, 
  xp_p1 = 0x2a2eb00 "M\206",
  xp_p2 = 0x1b07240 "`\"",
  xp_pad = "\000002\000\000\000\000`\"\000\000\000\000\000\000\001\000\000\000\000\020\000\000\0000q\001\000\000\000\000\001\000\000\000\000\000\000\000xq\001\000\000\000\000 ", '\0' <repeats 11 times>
, "\034", '\0' <repeats 11 times>, "\b\000\000\000\000\000\000\000\n\n4n\n4, '' <repeats 156 times>
}

(gdb) set $x = rtnl
(gdb) while ($x->next)
 >print $x->mon.mon_id.mon_name
 >set $x = $x->next  
 >end
$4 = 0x1b07e80 "10.10.52.21"
$5 = 0x2a2eab0 "10.10.52.23"
$6 = 0x2a2e9b0 "10.10.52.31"
$7 = 0x2b5b400 "10.10.52.18"
$8 = 0x2a34080 "10.10.52.12"
$9 = 0x1e63120 "10.10.52.30"
$10 = 0x2a332e0 "10.10.52.24"
$11 = 0x2a341e0 "10.10.52.50"
$12 = 0x2357d00 "10.10.52.22"
$13 = 0x1b07e60 "10.10.52.20"
$14 = 0x2a33220 "10.10.52.18"
$15 = 0x2a33170 "10.10.52.30"
$16 = 0x21100d0 "10.10.52.20"  
$17 = 0x2a32e10 "10.10.52.12"
$18 = 0x2a33110 "10.10.52.29"
$19 = 0x2a32e50 "10.10.52.25"
$20 = 0x2110210 "10.10.52.30"
$21 = 0x278b240 "10.10.52.25"
$22 = 0x2a33820 "10.10.52.24"
$23 = 0x1e63190 "10.10.52.30"
$24 = 0x2406b60 "10.10.52.50"
$25 = 0x29614f0 "10.10.52.50"
$26 = 0x2406ab0 "10.10.52.25"
$27 = 0x1b080a0 "10.10.52.29"
$28 = 0x2256f00 "10.10.52.24"
$29 = 0x2a2ea20 "10.10.52.22"
$30 = 0x255e470 "10.10.52.19"
$31 = 0x2a33b10 "10.10.52.28"
$32 = 0x2a2e8f0 "10.10.52.31"
$33 = 0x2a2e810 "10.10.52.31"
$34 = 0x2a2e730 "10.10.52.31"
$35 = 0x2a2e650 "10.10.52.31"
$36 = 0x2a2e570 "10.10.52.31"
$37 = 0x2a2e490 "10.10.52.31"
$38 = 0x2a2e3b0 "10.10.52.31"
$39 = 0x2a2e2d0 "10.10.52.31"
$40 = 0x2a2e1f0 "10.10.52.31"
$41 = 0x2a2e110 "10.10.52.31"
$42 = 0x2a2e030 "10.10.52.31"
$43 = 0x2a2df50 "10.10.52.31"
$44 = 0x2a2de70 "10.10.52.31"  
$45 = 0x2a2dd90 "10.10.52.31"
$46 = 0x2a2dcb0 "10.10.52.31"
$47 = 0x2a2dbd0 "10.10.52.31"
$48 = 0x2a2daf0 "10.10.52.31"
$49 = 0x2a2da10 "10.10.52.31"
$50 = 0x2a2d930 "10.10.52.31"  
...
$6949 = 0x28b42d0 "10.10.52.30"
$6950 = 0x28b41f0 "10.10.52.30"
...
$14429 = 0x271b010 "10.10.52.22"
$14430 = 0x271af30 "10.10.52.22"
...
$24804 = 0x24e3590 "10.10.52.25"
$24805 = 0x24e34b0 "10.10.52.25"
...
$28179 = 0x242ac70 "10.10.52.19"
$28180 = 0x242ab90 "10.10.52.19"
...
$44671 = 0x20a46f0 "10.10.52.20"
$44672 = 0x20a4610 "10.10.52.20"

Hmm, I think that list got a little longer than expected. What would be
causing this?

Simon-