Re: nagios and freebsd threads issue : help please ...

From: Christophe Yayon (lists_at_nbux.com)
Date: 08/21/05

  • Next message: Kamal R. Prasad: "Re: Project BSDVISION Wants To Develop Native *BSD Console Desktop" 
    Date: Sun, 21 Aug 2005 09:45:53 +0200
To: Christophe Yayon <lists@nbux.com>

    Hi again,

    I just upgraded again to FreeBSD5.4-Stable of August 20 and, i just
    killed a nagios loop process which consume 100% of CPU...
    The problem seems to persist again...

    How do think about this ?
    Thanks in advance.

    Christophe Yayon wrote:
    > Daniel,
    >
    >
    > But i am in stable '5.4-STABLE FreeBSD 5.4-STABLE #4: Tue Jul 5
    > 11:18:14 CEST 2005' and i have again the problem ...
    > The post is from Jun 22... I don't understant why i have again the
    > problem ?
    > Could u help me, please ?
    >
    > Thanks.
    >
    > Daniel Eischen wrote:
    >
    >> On Fri, 19 Aug 2005, Christophe Yayon wrote:
    >>
    >>
    >>> Hi all
    >>>
    >>> You should know about freebsd and nagios 2.0b threads issues (100% cpu
    >>> use by a forked process, lost check result, some pause of nagios main
    >>> process in certains obscursives conditions...).
    >>>
    >>> Some Nagios developpers says that the problem is in FreeBSD and some
    >>> other says that the problem is in nagios pthreads implementation, here a
    >>> resume of our discussions :
    >>> From
    >>>
    >>> http://www.opengroup.org/onlinepubs/009695399/functions/pthread_atfork.html
    >>>
    >>>
    >>> "It is suggested that programs that use fork() call an exec function
    >>> very soon afterwards in the child process, thus resetting all
    >>> states. In
    >>> the meantime, only a short list of async-signal-safe library routines
    >>> are promised to be available."
    >>>
    >>> Note *suggested*. This is a recommendation to protect against a shoddy
    >>> pthread-implementation. The thread specifications rule that only the
    >>> thread calling fork() is duplicated, which initially leads to the
    >>> recommendation (other threads holding locks aren't around to release
    >>> them in the new execution context).
    >>
    >>
    >>
    >> They choose to quote a weak reference to the actual requirement.
    >> The standard says (in the fork() section):
    >>
    >> A process shall be created with a single thread. If a
    >> multi-threaded process calls fork(), the new process shall
    >> contain a replica of the calling thread and its entire address
    >> space, possibly including the states of mutexes and other
    >> resources. Consequently, to avoid errors, the child process may
    >> only execute async-signal-safe operations until such time as one
    >> of the exec functions is called. Fork handlers may be
    >> established by means of the pthread_atfork() function in order
    >> to maintain application invariants across fork() calls.
    >>
    >
    >
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  • Next message: Kamal R. Prasad: "Re: Project BSDVISION Wants To Develop Native *BSD Console Desktop"

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