Re: [Boost-Users] Deadlocking problems with recursive_mutex on Linux with boost 1.2 9.0

From: William E. Kempf (wekempf_at_[hidden])
Date: 2002-12-05 11:10:21

John Maddock said:
>> One thing that confuses me... how does this even compile on Linux?  If
>> the pthread_mutexattr_settype function is available to the
>> compiler/linker, why on earth would it not function properly?
>> Definately need to do some research.
>>
>> Also, if you have a simple test case that reproduces the deadlock it
>> would be beneficial for you to send it to me for addition to the test
>> harness.
>>
>> > Since then everything is working quite perfectly!
>> >
>> > But I'd like to raise some questions:
>> > * Is my assumption correct that Linux doesn't have a proper support
>> for recursive POSIX mutexes?
>
> This is a really dumb question, but you did compile everything with
> -pthread didn't you?  Without that it will compile and link - but only
> to a thread unsafe "stub" runtime.  Or at least I think that's what
> happens :-(

That may well be what's happening here.  So there may be a third
alternative to those I gave before:  the documentation is incorrect,
pthread_mutexattr_settype does exist and does work properly, and the
boost::recursive_mutex does behave properly, and we've got a simple user
error.

> BTW don't the regression tests already test the recursive mutexes? (the
> tests are passing at the moment).

Yes, they do, and yes they are passing, but I was not discounting that the
tests might not be thorough enough to catch a race condition in the
implementation.  That's why I asked for a test case that would reproduce
his deadlock.

William E. Kempf