[Varnish] #1131: Strange bug with if/lookup - else/pass in vcl_recv

[Varnish]

#1131: Strange bug with if/lookup - else/pass in vcl_recv
-------------------------+--------------------------------------------------
 Reporter:  Guillaume.S  |        Type:  defect  
   Status:  new          |    Priority:  normal  
Milestone:               |   Component:  varnishd
  Version:  3.0.2        |    Severity:  normal  
 Keywords:               |  
-------------------------+--------------------------------------------------
 Hello,

 I have a strange bug with my vcl_recv :

 if(req.url ~ \.(png|gif|jpg|jpeg|css|js|PNG|GIF|JPG|JPEG|CSS|JS)$"){
         std.syslog(6, "++ RECV_IMG OK : "+req.http.host + req.url +" -- IP
 CLIENT : "+req.http.remote-ip);
         return (lookup);
 } else {
         std.syslog(6, "++ !RECV_NO-IMG : "+req.http.host + req.url +" --
 IP CLIENT : "+req.http.remote-ip);
         return (pass);
 }

 if i do a request in .php, i lost some time my cookie in response
 (the cookie disappear and our LB can't send the request to the good
 backend, so i have a new session on an other backend)
 I see the request use the "else/pass" way in the logs.

 But if i change "lookup" by "pass" in the "if", i did'nt loose the cookie
 anymore.
 if(req.url ~ \.(png|gif|jpg|jpeg|css|js|PNG|GIF|JPG|JPEG|CSS|JS)$"){
         std.syslog(6, "++ RECV_IMG OK : "+req.http.host + req.url +" -- IP
 CLIENT : "+req.http.remote-ip);
         return (pass);
 } else {
         std.syslog(6, "++ !RECV_NO-IMG : "+req.http.host + req.url +" --
 IP CLIENT : "+req.http.remote-ip);
         return (pass);
 }
 I always see the request use the "else/pass" way in the logs.

 Why my request was affected by the "if/lookup" ?

 I have this bug only when the server receive 20/30 requests/sec.
 With 2/3 requests, no bugs ...
 The server isn't loaded (2 x 8 Core, Load ~0.07) and i have free memory
 (malloc 44GB for Varnish / 48GB on server, i don't use more than 1.5GB
 today)

-- 
Ticket URL: <https://www.varnish-cache.org/trac/ticket/1131>
Varnish <https://varnish-cache.org/>
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