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Make recursion_check work for multiple threads 

With multiple threads, using an unprotected static variable to check
whether recursion has occured isn't valid, as one thread might have
modified the variable, thus causing another thread to incorrectly
conclude that recursion has occured.  This patch avoids this problem
by using a thread-specific variable for the recursion check.

Regtested on x86_64-pc-linux-gnu.

libgfortran/ChangeLog:

2018-11-23  Janne Blomqvist  <jb@gcc.gnu.org>

	* runtime/error.c (MAGIC): Remove.
	(recursion_key): New variable.
	(recursion_check): Use thread-specific variable for recursion
	check if threads are active.
	(constructor_recursion_check): New function.
	(destructor_recursion_check): New funcion.

From-SVN: r266419
This commit is contained in:
Janne Blomqvist 2018-11-23 22:42:03 +02:00
parent 70c70369ce
commit f4c0f88881
2 changed files with 47 additions and 9 deletions
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9
libgfortran/ChangeLog
View File

@ -1,3 +1,12 @@
2018-11-23 Janne Blomqvist <jb@gcc.gnu.org>
* runtime/error.c (MAGIC): Remove.
(recursion_key): New variable.
(recursion_check): Use thread-specific variable for recursion
check if threads are active.
(constructor_recursion_check): New function.
(destructor_recursion_check): New funcion.
2018-11-22 Janne Blomqvist <jb@gcc.gnu.org>
* acinclude.m4 (LIBGFOR_CHECK_ATOMIC_FETCH_ADD): Rename and test

47
libgfortran/runtime/error.c
View File

@ -332,22 +332,51 @@ show_locus (st_parameter_common *cmp)
/* recursion_check()-- It's possible for additional errors to occur
* during fatal error processing. We detect this condition here and
* exit with code 4 immediately. */
* abort immediately. */
#define MAGIC 0x20DE8101
static __gthread_key_t recursion_key;
static void
recursion_check (void)
{
static int magic = 0;
/* Don't even try to print something at this point */
if (magic == MAGIC)
sys_abort ();
magic = MAGIC;
if (__gthread_active_p ())
{
bool* p = __gthread_getspecific (recursion_key);
if (!p)
{
p = xcalloc (1, sizeof (bool));
__gthread_setspecific (recursion_key, p);
}
if (*p)
sys_abort ();
*p = true;
}
else
{
static bool recur;
if (recur)
sys_abort ();
recur = true;
}
}
#ifdef __GTHREADS
static void __attribute__((constructor))
constructor_recursion_check (void)
{
if (__gthread_active_p ())
__gthread_key_create (&recursion_key, &free);
}
static void __attribute__((destructor))
destructor_recursion_check (void)
{
if (__gthread_active_p ())
__gthread_key_delete (recursion_key);
}
#endif
#define STRERR_MAXSZ 256