[Bug 675185] Re: [Hardy SRU] dash bug causes mysqld_safe to spin at 100% CPU

[Gabriel Ramirez]

Hello, we apologize for the delayed response, but as Ubuntu has moved on
from upstart to systemd, it will not affect newer releases in the same
way so we will close this one out

** Changed in: mysql-5.1 (Ubuntu)
       Status: Confirmed => Invalid

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Title:
  [Hardy SRU] dash bug causes mysqld_safe to spin at 100% CPU

Status in Maria:
  Fix Released
Status in Percona Server:
  Invalid
Status in Percona Server 5.1 series:
  Invalid
Status in Percona Server 5.5 series:
  Invalid
Status in dash package in Ubuntu:
  Invalid
Status in mysql-5.1 package in Ubuntu:
  Invalid

Bug description:
  Symptoms are: After mysql server upgrades + restarts the old mysqld_safe keeps running and consumes 100% cpu, strace shows:
  wait4(4294967295, 0x7fffb3b3d59c, 0, NULL) = -1 ECHILD (No child ...
  wait4(4294967295, 0x7fffb3b3d59c, 0, NULL) = -1 ECHILD (No child ...
  wait4(4294967295, 0x7fffb3b3d59c, 0, NULL) = -1 ECHILD (No child ...
  For more info see the dupes, particularily bug 105457. Does not happen always, for reliable test case see below.

  This is a bug (race condition) in dash, partly fixed by
  http://git.kernel.org/?p=utils/dash/dash.git;a=commit;h=3800d4934391b144fd261a7957aea72ced7d47ea
  . This fixes the test case and mysqld_safe, but introduces another
  regression: http://eeek.borgchat.net/lists/dash/msg00268.html (patch
  for that in the thread)

  TEST CASE: Script in the commit message (link above). Allows to
  reproduce this always, even on Karmic still.

  (Proposed fix of using #!/bin/bash instead of #!/bin/sh is not as
  straigtforward as expected. bash called as sh goes into sh
  compatibility mode, called as bash it may behave subtle differently)

  NOTES: mysqld_safe was replaced by an upstart job in Lucid. But Hardy
  has support for 3 more years, justifiying a fix.

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