[Varnish] #1047: regsuball, infinite loops and confusing behaviours

Varnish varnish-bugs at varnish-cache.org
Sun Oct 30 14:37:07 CET 2011

#1047: regsuball, infinite loops and confusing behaviours
 Reporter:  ctrix             |        Type:  defect  
   Status:  new               |    Priority:  normal  
Milestone:                    |   Component:  varnishd
  Version:  3.0.2             |    Severity:  normal  
 Keywords:  regsuball freeze  |  
 Something like the following:

   regsuball(req.http.Cookie, "^[;]*", "");

 Causes a tight loop that never exits, consumong all CPU and exhausting all
 available slots for the clients.

 The cause is that the regexp always match and that the fix is trivial.
 Less trivial is to understand the problem while debugging the hangs.

 I suggest as a fix to break the loop somewhere or, at least, add a warning
 in the logs.

 (this was spotted on a 3.0.2, if it matters).

Ticket URL: <https://www.varnish-cache.org/trac/ticket/1047>
Varnish <https://varnish-cache.org/>
The Varnish HTTP Accelerator

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