mysterious hang in pthread_create

[Andriy Gapon]

on 01/09/2008 14:12 Kostik Belousov said the following:
> On Mon, Sep 01, 2008 at 01:53:23PM +0300, Andriy Gapon wrote:
>> on 01/09/2008 11:45 Kostik Belousov said the following:
>>> On Mon, Sep 01, 2008 at 11:34:45AM +0300, Andriy Gapon wrote:
>>>> on 01/09/2008 11:10 David Xu said the following:
>>>>> The ancient bug is in rtld, rlock_acquire() and wlock_acquire() test
>>>>> thread_flag as a boolean value, because pt_iterate_phdr() tries to
>>>>> lock two locks at same time, this test will always fail once it
>>>>> acquired first lock.
>>>>>
>>>>> The following silly patch fixes the problem Andriy encountered:
>>>> I can confirm - this fixed the issue for me.
>>>> David, thanks!
>>> Does libc_r still work with patch applied ?
>> In what sense?
>> The test program that I posted seems to hang in both cases (patched and 
>> unpatched rtld).
> 
> The David' patch changes the code used to support libc_r operations.
> Even on CURRENT, if you run 4.x-compiled binary with the support of
> compat-4x libraries, this code from /libexec/ld-elf.so.1 (installed
> by CURRENT buildworld) provides locking for rtld.

I understand, but I am not sure what exactly needs to be tested.
"Still works" is too broad in this context.

-- 
Andriy Gapon