Backport r60148 and r65481: sanity checks to avoid infinite loops.
diff --git a/Python/pystate.c b/Python/pystate.c
index 086789d..da417c1 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -240,6 +240,7 @@
{
PyInterpreterState *interp;
PyThreadState **p;
+ PyThreadState *prev_p = NULL;
if (tstate == NULL)
Py_FatalError("PyThreadState_Delete: NULL tstate");
interp = tstate->interp;
@@ -252,6 +253,19 @@
"PyThreadState_Delete: invalid tstate");
if (*p == tstate)
break;
+ /* Sanity check. These states should never happen but if
+ * they do we must abort. Otherwise we'll end up spinning in
+ * in a tight loop with the lock held. A similar check is done
+ * in thread.c find_key(). */
+ if (*p == prev_p)
+ Py_FatalError(
+ "PyThreadState_Delete: small circular list(!)"
+ " and tstate not found.");
+ prev_p = *p;
+ if ((*p)->next == interp->tstate_head)
+ Py_FatalError(
+ "PyThreadState_Delete: circular list(!) and"
+ " tstate not found.");
}
*p = tstate->next;
HEAD_UNLOCK();