Re: radiusd: Error detected by libpthread: Invalid mutex.

[christos%astron.com@localhost (Christos Zoulas)]

In article <20130430124431.GF82407%trav.math.uni-bonn.de@localhost>,
Edgar Fuß  <ef%math.uni-bonn.de@localhost> wrote:
>> It is prolly a radiusd bug:
>Maybe yes. See below.
>
>> $ PTHREAD_DIAGASSERT=a radiusd
>> $ gdb radiusd radiusd.core
>Unfortunately, this (with allow_core_dumps=yes in radiusd.conf) doesn't give
>me a core dump.
>
>The problem seems to be that radiusd sets up mutexes (pthread_mutex_init)
>while reading the config file. It reads the config file before fork()ing
>in order to daemonize. In fact, running it with -f and then manually
>backgrounding it makes the problem disappear.
>Also, moving the config-file reading code below the fork() also helps.
>
>Before reporting a bug to the FreeRADIUS people: It looks weird to me to
>create a mutex, then fork and use the mutex in the child process. However,
>I'm unsure whether this is really illegal (I can't find anything saying so
>besides the sheer existance of pthread_atfork(), which radiusd doesn't call)
>or a problem with NetBSD's implementation.
>
>Any pthread experts to help me?

It is implementation dependend; for portability pthread_mutex_init() should
be done in the child process and not cross a fork. Eg:

http://www.sbin.org/doc/glibc/libc_34.html
http://stackoverflow.com/questions/2620313/how-to-use-pthread-atfork-and-pthread-once-to-reinitialize-mutexes-in-child

Please file a PR to add a note in our man pages.

christos