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Date: Mon, 01 Sep 2008 11:34:45 +0300
From: Andriy Gapon <avg@icyb.net.ua>
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To: David Xu <davidxu@freebsd.org>
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Cc: Daniel Eischen <deischen@freebsd.org>, freebsd-threads@freebsd.org
Subject: Re: mysterious hang in pthread_create
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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!

> Index: rtld_lock.c
> ===================================================================
> --- rtld_lock.c    （版本 182594）
> +++ rtld_lock.c    （工作副本）
> @@ -184,7 +184,7 @@
>  int
>  rlock_acquire(rtld_lock_t lock)
>  {
> -    if (thread_mask_set(lock->mask)) {
> +    if (thread_mask_set(lock->mask) & lock->mask) {
>          dbg("rlock_acquire: recursed");
>          return (0);
>      }
> @@ -195,7 +195,7 @@
>  int
>  wlock_acquire(rtld_lock_t lock)
>  {
> -    if (thread_mask_set(lock->mask)) {
> +    if (thread_mask_set(lock->mask) & lock->mask) {
>          dbg("wlock_acquire: recursed");
>          return (0);
>      }
> 
> 
> Regards,
> David Xu
> 


-- 
Andriy Gapon