Bug #16372 server crashes when test 'conc_sys' is running

Description:
running the test suite 'conc_sys' crashed the server:

 The instruction at "0x004a5bc3" referenced memory at "0x008000390". 
 The memory could not be "read".

This issue is reported at the first occurrency, I try to reproduce it now and will try to provide a reduced test for easier reproduction.

How to repeat:
- bk clone mysql-test-extra-5.0
- start the server on Windows, using e.g. the script from the 'system_1 ' test suite
- start the client on a Linux machine in directory 'mysql-test': run-conc_sys.sh (after changing the values inside.
- more details and hopefully some scripts will be provided later after better analyzing the crash

Suggested fix:
fix the crashing server

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/5069

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/5629

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/5630

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/5930

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/6040

Fixed in 4.1.20, 5.0.22, 5.1.11.

Noted in 4.1.20, 5.0.22, 5.1.11 changelogs.

Concurrent reading and writing of privilege structures could
crash the server.