Author: Armin Rigo <[email protected]>
Branch: ec-keepalive
Changeset: r81568:18bd10183487
Date: 2016-01-05 08:39 +0000
http://bitbucket.org/pypy/pypy/changeset/18bd10183487/
Log: After fork(), at least in the __thread case, we need to be careful
and reinitialize the doubly-linked list. Otherwise, it points to old
__thread structures, which are silently gone from memory.
diff --git a/rpython/translator/c/src/threadlocal.c
b/rpython/translator/c/src/threadlocal.c
--- a/rpython/translator/c/src/threadlocal.c
+++ b/rpython/translator/c/src/threadlocal.c
@@ -12,12 +12,16 @@
manipulation (because such manipulations can occur without the GIL) */
static long pypy_threadlocal_lock = 0;
+static int check_valid(void);
+
void _RPython_ThreadLocals_Acquire(void) {
while (!lock_test_and_set(&pypy_threadlocal_lock, 1)) {
/* busy loop */
}
+ assert(check_valid());
}
void _RPython_ThreadLocals_Release(void) {
+ assert(check_valid());
lock_release(&pypy_threadlocal_lock);
}
@@ -34,6 +38,43 @@
&linkedlist_head, /* prev */
&linkedlist_head }; /* next */
+static int check_valid(void)
+{
+ struct pypy_threadlocal_s *prev, *cur;
+ prev = &linkedlist_head;
+ while (1) {
+ cur = prev->next;
+ assert(cur->prev == prev);
+ if (cur == &linkedlist_head)
+ break;
+ assert(cur->ready == 42);
+ assert(cur->next != cur);
+ prev = cur;
+ }
+ assert(cur->ready == -1);
+ return 1;
+}
+
+static void cleanup_after_fork(void)
+{
+ /* assume that at most one pypy_threadlocal_s survived, the current one */
+ struct pypy_threadlocal_s *cur;
+#ifdef USE___THREAD
+ cur = &pypy_threadlocal;
+#else
+ cur = (struct pypy_threadlocal_s *)_RPy_ThreadLocals_Get();
+#endif
+ if (cur && cur->ready == 42) {
+ cur->next = cur->prev = &linkedlist_head;
+ linkedlist_head.next = linkedlist_head.prev = cur;
+ }
+ else {
+ linkedlist_head.next = linkedlist_head.prev = &linkedlist_head;
+ }
+ _RPython_ThreadLocals_Release();
+}
+
+
struct pypy_threadlocal_s *
_RPython_ThreadLocals_Enum(struct pypy_threadlocal_s *prev)
{
@@ -149,7 +190,7 @@
#ifndef _WIN32
pthread_atfork(_RPython_ThreadLocals_Acquire,
_RPython_ThreadLocals_Release,
- _RPython_ThreadLocals_Release);
+ cleanup_after_fork);
#endif
}
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