Re: [LMDB] Lockups with robust mutexes and crashing processes

[Howard Chu <hyc@symas.com>]

Marcos-David Dione wrote:
> "openldap-devel" <openldap-devel-bounces@openldap.org> wrote on
> 25/11/2014 16:19:40:
>  > Fyi, this would not have been a bug in Solaris:
>  >
>  > https://docs.oracle.com/cd/E19253-01/816-5168/pthread-mutexattr-
>  > setrobust-np-3c/index.html
>
>          you mean, because of the phrase «When the owner of a mutex with
> the PTHREAD_MUTEX_ROBUST_NP /robustness/ attribute dies, or when the
> process containing such a locked mutex unmaps the memory containing the
> mutex or performs one of the _exec(2)_
> <https://docs.oracle.com/docs/cd/E19253-01/816-5167/exec-2/index.html>functions,
> the mutex is unlocked.»? I'm not sure that when it says 'unmap' it means
> 'munmap()s'.

There is no other meaning of the word. A process-shared mutex must 
reside in shared memory. When a process detaches from that shared 
memory, it is unmapped.

--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/