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$NetBSD: patch-lib_thread.c,v 1.1 2019/09/30 08:57:49 kardel Exp $
- add fast check on prev/next pointer invariants
- add check to detect inserting of a thread already in a list
- add check to detect deletion of a thread not in a list
- ignore cancellation requests for the currently running thread (fixes crash)
- fix setting of prey/next pointers on adjecant elements when a head/tail element is
deleted
--- lib/thread.c.orig 2018-02-19 21:24:55.000000000 +0000
+++ lib/thread.c
@@ -531,6 +531,10 @@ thread_master_create ()
return NULL;
}
+ rv->ready.name = "ready";
+ rv->event.name = "event";
+ rv->unuse.name = "unuse";
+
rv->fd_limit = (int)limit.rlim_cur;
rv->read = XCALLOC (MTYPE_THREAD, sizeof (struct thread *) * rv->fd_limit);
if (rv->read == NULL)
@@ -560,6 +564,11 @@ thread_master_create ()
static void
thread_list_add (struct thread_list *list, struct thread *thread)
{
+ if (thread->list) {
+ zlog_err("%s:%d: thread_list_add INCONSISTENCY thread %p is already linked in list %s", __FILE__, __LINE__, thread, thread->list->name);
+ assert(!thread->list);
+ }
+
thread->next = NULL;
thread->prev = list->tail;
if (list->tail)
@@ -568,22 +577,57 @@ thread_list_add (struct thread_list *lis
list->head = thread;
list->tail = thread;
list->count++;
+ thread->list = list;
}
/* Delete a thread from the list. */
static struct thread *
thread_list_delete (struct thread_list *list, struct thread *thread)
{
+ if (!thread->list) {
+ zlog_err("%s:%d: thread_list_delete INCONSISTENCY thread %p is NOT linked in a list", __FILE__, __LINE__, thread);
+ assert(thread->list);
+ }
+
+ if (thread->list && thread->list != list) {
+ zlog_err("%s:%d: thread_list_delete INCONSISTENCY thread %p is linked in list %s but should be removed from list %s",
+ __FILE__, __LINE__, thread, thread->list->name, list->name);
+ assert(thread->list == list);
+ }
+
if (thread->next)
thread->next->prev = thread->prev;
- else
+ else {
+ if (list->tail != thread) {
+ zlog_debug("%s:%d: thread_list_delete INCONSISTENCY thread %p has no successor but list->tail points to %p in list %s",
+ __FILE__, __LINE__, thread, list->tail, list->name);
+ assert(list->tail == thread);
+ }
+
list->tail = thread->prev;
+ if (list->tail)
+ list->tail->next = NULL;
+ }
+
if (thread->prev)
thread->prev->next = thread->next;
- else
+ else {
+ if (list->head != thread) {
+ zlog_debug("%s:%d: thread_list_delete INCONSISTENCY thread %p has no predecessor but list->head points to %p in list %s",
+ __FILE__, __LINE__, thread, list->head, list->name);
+ assert(list->head == thread);
+ }
+
list->head = thread->next;
- thread->next = thread->prev = NULL;
+ if (list->head)
+ list->head->prev = NULL;
+ }
+
list->count--;
+
+ thread->next = thread->prev = NULL;
+ thread->list = NULL;
+
return thread;
}
@@ -603,10 +647,12 @@ thread_add_fd (struct thread **thread_ar
static void
thread_add_unuse (struct thread *thread)
{
- thread->type = THREAD_UNUSED;
assert (thread->master != NULL && thread != NULL);
+ assert (thread_current != thread);
assert (thread->next == NULL);
assert (thread->prev == NULL);
+ assert (thread->list == NULL);
+ thread->type = THREAD_UNUSED;
thread_list_add (&thread->master->unuse, thread);
}
@@ -948,7 +994,15 @@ thread_cancel (struct thread *thread)
struct thread_list *list = NULL;
struct pqueue *queue = NULL;
struct thread **thread_array = NULL;
-
+
+ /*
+ * we cannot cancel ourself when running.
+ * cancellation of ourself would lead to a double entry attempt
+ * into the unuse list.
+ */
+ if (thread_current == thread)
+ return;
+
switch (thread->type)
{
case THREAD_READ:
@@ -1175,7 +1229,7 @@ thread_fetch (struct thread_master *m)
exceptfd = fd_copy_fd_set(m->exceptfd);
/* Calculate select wait timer if nothing else to do */
- if (m->ready.count == 0)
+ if (thread_empty(&m->ready))
{
quagga_get_relative (NULL);
timer_wait = thread_timer_wait (m->timer, &timer_val);
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