Condition(v1l->niov < v1l->siov) not true

[joshuaspence]

We are seeing panics on Varnish 5.1.1. Here is the stack trace:

Panic at: Wed, 22 Mar 2017 22:54:00 GMT
Assert error in V1L_Chunked(), http1/cache_http1_line.c line 274:
  Condition(v1l->niov < v1l->siov) not true.
version = varnish-5.1.1 revision de38712, vrt api = 6.0
ident = Linux,4.4.0-62-generic,x86_64,-junix,-smalloc,-smalloc,-hcritbit,epoll
now = 86524.289610 (mono), 1490223240.320110 (real)
Backtrace:
  0x438b37: /usr/sbin/varnishd() [0x438b37]
  0x45bbf5: /usr/sbin/varnishd(V1L_Chunked+0x135) [0x45bbf5]
  0x458fc9: /usr/sbin/varnishd(V1D_Deliver+0x3d9) [0x458fc9]
  0x43c541: /usr/sbin/varnishd(CNT_Request+0x221) [0x43c541]
  0x45a867: /usr/sbin/varnishd() [0x45a867]
  0x451b69: /usr/sbin/varnishd() [0x451b69]
  0x451feb: /usr/sbin/varnishd() [0x451feb]
  0x7fc6cd6896ba: /lib/x86_64-linux-gnu/libpthread.so.0(+0x76ba) [0x7fc6cd6896ba]
  0x7fc6cd3bf82d: /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7fc6cd3bf82d]
thread = (cache-worker)
thr.req = 0x7fc4a09f9020 {
  vxid = 1842984, transport = HTTP/1 {
    state = HTTP1::Proc
  }
  step = R_STP_TRANSMIT,
  req_body = R_BODY_NONE,
  restarts = 0, esi_level = 0,
  sp = 0x7fc587ef5a20 {
    fd = 89, vxid = 1842983,
    t_open = 1490223239.797381,
    t_idle = 1490223239.797381,
    transport = HTTP/1 {
      state = HTTP1::Proc
    }
    client = 10.155.20.108 50237,
  },
  worker = 0x7fc6c192fc70 {
    stack = {0x7fc6c1930000 -> 0x7fc6c1924000},
    ws = 0x7fc6c192fe70 {
      id = \"wrk\",
      {s, f, r, e} = {0x7fc6c192f410, +0, (nil), +2040},
    },
    VCL::method = DELIVER,
    VCL::return = deliver,
    VCL::methods = {RECV, HASH, MISS, DELIVER},
  },
  ws = 0x7fc4a09f9208 {
    id = \"req\",
    {s, f, r, e} = {0x7fc4a09fb008, +57312, +57328, +57328},
  },
  http_conn = 0x7fc4a09f9130 {
    fd = 89 (@0x7fc587ef5a38),
    doclose = NULL,
    ws = 0x7fc4a09f9208 {
      [Already dumped, see above]
    },
    {rxbuf_b, rxbuf_e} = {0x7fc4a09fb008, 0x7fc4a09fc71f},
    {pipeline_b, pipeline_e} = {(nil), (nil)},
    content_length = -1,
    body_status = none,
    first_byte_timeout = 0.000000,
    between_bytes_timeout = 0.000000,
  },
  http[req] = 0x7fc4a09f92a0 {
    ws = 0x7fc4a09f9208 {
      [Already dumped, see above]
    },
    hdrs {
      REDACTED
    },
  },
  http[resp] = 0x7fc4a09f9b90 {
    ws = 0x7fc4a09f9208 {
      [Already dumped, see above]
    },
    hdrs {
      \"HTTP/1.1\",
      \"200\",
      \"OK\",
      \"Date: Wed, 22 Mar 2017 22:54:00 GMT\",
      \"Content-Type: text/html; charset=UTF-8\",
      \"Vary: Accept-Encoding, X-Authenticated\",
      \"x-chosenlang: domain=en\",
      \"Cache-Control: public, max-age=180\",
      \"Age: 0\",
      \"X-Cache: MISS\",
      \"Accept-Ranges: bytes\",
      \"Transfer-Encoding: chunked\",
      \"Connection: keep-alive\",
    },
  },
  vcl = {
    name = \"rootroot9edccf72-2957-461d-b856-d5d4bec8dfa4\",
    busy = 166,
    discard = 0,
    state = auto,
    temp = warm,
    conf = {
      srcname = {
        \"/etc/varnish/default.vcl\",
        \"Builtin\",
        REDACTED
      },
    },
  },
  vmods = {
    directors = {Varnish 5.1.1 de38712, 6.0},
    cookie = {Varnish 5.1.1 de38712, 6.0},
    std = {Varnish 5.1.1 de38712, 6.0},
  },
  objcore[REQ] = 0x7fc49a5d5920 {
    refcnt = 3,
    flags = {},
    exp_flags = {refd},
    boc = 0x7fc6a08d5560 {
      refcnt = 2,
      state = stream,
      vary = (nil),
      stevedore_priv = (nil),
    },
    exp = {1490223240.319970, 180.000000, 10.000000, 0.000000},
    objhead = 0x7fc52d7b4f90,
    stevedore = 0x7fc6cc8363c0 (malloc s0) {
      Simple = 0x7fc69e74fb40,
      Obj = 0x7fc4e9e501f8 {priv=0x7fc4e9e501f0, ptr=0x7fc69e74fb40, len=444, space=448},
      LEN = 0x0...0,
      VXID = 0x001c1f29,
      FLAGS = 0x02,
      GZIPBITS = 0x0...0,
      LASTMODIFIED = 0x41d634c022000000,
      VARY = {len=0, ptr=0x7fc69e74fbb8},
      HEADERS = {len=0, ptr=0x7fc69e74fbec},
      Body = 0x7fc4e9e50248 {priv=0x7fc4e9e50240, ptr=0x7fc482977000, len=0, space=16384},
    },
  },
  flags = {
  },
},
thr.busyobj = (nil) {
},

[joshuaspence]

Actually, it looks like this is the same as #2207, which was supposedly fixed by a6696fc.

[joshuaspence]

Thanks. Would you happen to know when the next release can be expected?

[hermunn]

Backport review: This is connected to #2207, and has been handled.