[Varnish] #1831: random Panic's at recent master

[Varnish]

#1831: random Panic's at recent master
------------------------+----------------------
 Reporter:  hjanuschka  |       Type:  defect
   Status:  new         |   Priority:  normal
Milestone:              |  Component:  varnishd
  Version:  trunk       |   Severity:  normal
 Keywords:              |
------------------------+----------------------
 Child (38439) Panic at: Tue, 15 Dec 2015 08:07:03 GMT#012"Assert error in
 VDP_bytes(), cache/cache_deliver_proc.c line 49:#012  Condition(act >
 VDP_NULL || len > 0) not true.#012thread = (cache-worker)#012version =
 varnish-trunk revision 2c76f5b#012ident =
 Linux,3.16.0-4-amd64,x86_64,-jnone,-smalloc,-smalloc,-hcritbit,epoll#012Backtrace:#012
 0x431d12: pan_ic+0x152#012  0x41a598: VDP_bytes+0xb8#012  0x4624c2:
 sml_iterator+0x252#012  0x44b498: V1D_Deliver+0x228#012  0x4343bf:
 cnt_vdp+0x11f#012  0x435aa6: CNT_Request+0x1496#012  0x44c0d3:
 HTTP1_Session+0xd3#012  0x437f01: SES_Proto_Req+0x61#012  0x446b6a:
 WRK_Thread+0x45a#012  0x446fbb: pool_thread+0x2b#012req = 0x7fb3e81a6460
 {#012  vxid = 10649615, step = R_STP_DELIVER,#012  req_body =
 R_BODY_NONE,#012  restarts = 0, esi_level = 0,#012  sp = 0x7fb3e81a6250
 {#012    fd = 468, vxid = 10649614,#012    client = 92.123.224.148
 55483,#012    step = S_STP_H1PROC,#012  },#012  worker = 0x7fb3dd978cc0
 {#012    stack = {0x7fb3dd979000 -> 0x7fb3dd96d000},#012    ws =
 0x7fb3dd978eb8 {#012      id = \"wrk\",#012      {s,f,r,e} =
 {0x7fb3dd978460,0x7fb3dd978460,(nil),+2040},#012    },#012    VCL::method
 = DELIVER,#012    VCL::return = deliver,#012    VCL::methods = {RECV,
 HASH, HIT, DELIVER},#012  },#012  ws = 0x7fb3e81a6640 {#012    id =
 \"req\",#012    {s,f,r,e} = {0x7fb3e81a8440,+2536,+57336,+57336},#012
 },#012  http_conn = 0x7fb3e81a6568 {#012    fd = 468,#012    doclose =
 NULL,#012    ws = 0x7fb3e81a6640,#012    {rxbuf_b, rxbuf_e} =
 {0x7fb3e81a8440, 0x7fb3e81a8990},#012    {pipeline_b, pipeline_e} =
 {(nil), (nil)},#012    content_length = -1,#012    body_status = none,#012
 first_byte_timeout = 0.000000,#012    between_bytes_timeout =
 0.000000,#012  },#012  http[req] = 0x7fb3e81a66d8 {#012    ws[req] =
 0x7fb3e81a6640,#012    hdrs {#012      \"GET\",#012
 \"/static/sid/438/kmprog/index.xml\",#012      \"HTTP/1.1\",#012
 \"If-Modified-Since: Tue, 15 Dec 2015 07:55:36 GMT\",#012      \"Accept:
 */*\",#012      \"Pragma: no-cache\",#012      \"Expires: 0\",#012
 \"Last-Modified: Thu Jan 01 1970 01:00:00 GMT+0100
 (Mitteleurop\303\244ische Zeit)\",#012      \"Referer:
 http://www.krone.at/\",#012      \"Accept-Language: de-DE\",#012
 \"User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0)
 like Gecko\",#012      \"True-Client-IP: 93.220.47.198\",#012      \"X
 -Akamai-CONFIG-LOG-DETAIL: true\",#012      \"TE:  chunked;q=1.0\",#012
 \"Connection: TE, keep-alive\",#012      \"Akamai-Origin-Hop: 2\",#012
 \"Via: 1.1 v1-akamaitech.net(ghost) (AkamaiGHost), 1.1 akamai.net(ghost)
 (AkamaiGHost)\",#012      \"Host: www.krone.at\",#012      \"Accept-
 Encoding: gzip\",#012      \"X-Forwarded-For: 93.220.47.198, 84.53.136.40,
 92.123.224.148, 92.123.224.148\",#012      \"X-passthrough-headers:
 yes\",#012      \"X-Varnish-TTL: 899.954\",#012      \"X-Varnish-Cache:
 HIT\",#012    },#012  },#012  http[resp] = 0x7fb3e81a6fc8 {#012    ws[req]
 = 0x7fb3e81a6640,#012    hdrs {#012      \"HTTP/1.1\",#012
 \"200\",#012      \"OK\",#012      \"Date: Tue, 15 Dec 2015 08:07:02
 GMT\",#012      \"Last-Modified: Tue, 15 Dec 2015 08:06:13 GMT\",#012
 \"Cache-Control: max-age=480\",#012      \"Expires: Tue, 15 Dec 2015
 08:15:02 GMT\",#012      \"Content-Type: text/xml\",#012      \"x-url:
 /static/sid/438/kmprog/index.xml\",#012      \"x-host: www.krone.at\",#012
 \"X-Varnish-BE: hps_director\",#012      \"Content-Encoding: gzip\",#012
 \"Vary: Accept-Encoding\",#012      \"Age: 0\",#012      \"X-Varnish-Node:
 asgard\",#012      \"X-Varnish-TTL: 899.954\",#012      \"X-Varnish-Cache:
 HIT\",#012      \"Connection: close\",#012      \"Server: Varnish\",#012
 \"X-Powered-By: Curiosity\",#012      \"Accept-Ranges: bytes\",#012
 \"Content-Length: 124\",#012    },#012  },#012  vcl = {#012    temp =
 warm#012    srcname = {#012      \"input\",#012      \"Builtin\",#012
 \"/opt/varnish/confs/backends.vcl\",#012
 \"/opt/varnish/confs/security/vfw.vcl\",#012
 \"/opt/varnish/confs/security/protocol.vcl\",#012
 \"/opt/varnish/confs/security/paths.vcl\",#012
 \"/opt/varnish/confs/security/generic.vcl\",#012
 \"/opt/varnish/confs/security/sql.vcl\",#012
 \"/opt/varnish/confs/security/xss.vcl\",#012
 \"/opt/varnish/confs/node.vcl\",#012    },#012  },#012  objcore[REQ] =
 0x7fb3e81334f0 {#012    refcnt = 2,#012    flags = 0x0,#012    objhead =
 0x7fb3e81333a0,#012    stevedore = 0xd08d90 (malloc s0),#012  },#012
 flags = {#012    is_hit,#012  },#012},#012#012"


 recently upgraded to master and now my logs are receiving the following
 panic from time to time resulting in a crash

-- 
Ticket URL: <https://www.varnish-cache.org/trac/ticket/1831>
Varnish <https://varnish-cache.org/>
The Varnish HTTP Accelerator