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bionic: fix __get_tls( ) crash issue

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When running the stress test of pthread create/destroy, a crash may
oocur in __get_tls(). That is caused by the race condition with __set_tls( ):

Author: Jack Ren <jack.ren@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
This commit is contained in:
Jack Ren 2011-08-01 18:44:55 +08:00 committed by Jean-Baptiste Queru
parent 897815a1fe
commit 31e72bc328
1 changed files with 5 additions and 0 deletions
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5
libc/arch-x86/bionic/__set_tls.c
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@ -60,6 +60,8 @@ static struct user_desc _tls_desc =
0 0
}; };
static pthread_mutex_t _tls_desc_lock = PTHREAD_MUTEX_INITIALIZER;
struct _thread_area_head { struct _thread_area_head {
void *self; void *self;
}; };
@ -71,6 +73,7 @@ int __set_tls(void *ptr)
{ {
int rc, segment; int rc, segment;
pthread_mutex_lock(&_tls_desc_lock);
_tls_desc.base_addr = (unsigned long)ptr; _tls_desc.base_addr = (unsigned long)ptr;
/* We also need to write the location of the tls to ptr[0] */ /* We also need to write the location of the tls to ptr[0] */
@ -88,6 +91,8 @@ int __set_tls(void *ptr)
asm __volatile__ ( asm __volatile__ (
" movw %w0, %%gs" :: "q"(segment) " movw %w0, %%gs" :: "q"(segment)
); );
pthread_mutex_unlock(&_tls_desc_lock);
return 0; return 0;
} }