[Varnish] #1055: Long values of shm_reclen is unsafe

Varnish varnish-bugs at varnish-cache.org
Wed Nov 9 15:32:21 CET 2011

#1055: Long values of shm_reclen is unsafe
 Reporter:  kristian  |       Owner:       
     Type:  defect    |      Status:  new  
 Priority:  normal    |   Milestone:       
Component:  varnishd  |     Version:  trunk
 Severity:  normal    |    Keywords:       

Comment(by kristian):


 Part of the problem is that shm_reclen is evaluated directly, even though
 the shm_workspace is only adjusted when the thread starts.

 In addition, the shm_workspace seems largely unrelated to shm_reclen.
 There's nothing stopping you from shm_reclen=65k shm_workspace=4k, and
 that will of course break.

 All in all, it's VERY unadvised to use shm_reclen larger than, say, 16kB
 now. The code is simply too fragile. And you must increase the
 shm_workspace too, and do it /before/ starting Varnish - or starting the
 threads at least.

Ticket URL: <https://www.varnish-cache.org/trac/ticket/1055#comment:1>
Varnish <https://varnish-cache.org/>
The Varnish HTTP Accelerator

More information about the varnish-bugs mailing list