mysterious hang in pthread_create

Andriy Gapon avg at icyb.net.ua
Mon Sep 1 08:34:54 UTC 2008


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


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