[Bug 1218641] Re: dhclient uses 100% cpu when ipv6 is not igored

[Oli Wade]

Version "4.1.ESV-R4-0ubuntu5.8" in Precise (12.04).

** Package changed: ubuntu => isc-dhcp (Ubuntu)

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Title:
  dhclient uses 100% cpu when ipv6 is not igored

Status in “isc-dhcp” package in Ubuntu:
  New

Bug description:
  When network manager is set so "automatic" or "automatic (addresses
  only)" for ipv6, dhclient is observed to use 100% CPU.

  There are no apparent errors in the syslog. Setting ipv6 to "ignore"
  solves the problem.

  When it is not ignored, ipv6 addressing seems to complete (both dhcp
  and sac); when it is ignored only the sac address gets configured.

  Typical "top" output without ignoring ipv6:
  ====
  top - 22:51:11 up 20 min,  2 users,  load average: 2.43, 2.85, 2.15
  Tasks: 158 total,   3 running, 155 sleeping,   0 stopped,   0 zombie
  Cpu(s): 48.2%us, 22.6%sy,  0.0%ni, 29.2%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
  Mem:   1015240k total,   913120k used,   102120k free,    41016k buffers
  Swap:  1648636k total,    18388k used,  1630248k free,   398052k cached

    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
   2981 root      20   0  2924 1352 1040 R   99  0.1  12:10.90 dhclient           
   2382 i         20   0  771m 171m  31m S   10 17.3   2:36.07 firefox   
  ====

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