Re: [patch] ptrace-fix-2.5.33-A1

From: Ingo Molnar (mingo@elte.hu)
Date: Thu Sep 05 2002 - 17:58:56 EST

i've attached a combined patch of your two patches, against BK-curr. Looks
good to me, and since it passed your more complex ptrace tests ...

        Ingo

--- linux/kernel/exit.c.orig Fri Sep 6 00:55:02 2002
+++ linux/kernel/exit.c Fri Sep 6 00:57:58 2002
@@ -66,6 +66,11 @@
         atomic_dec(&p->user->processes);
         security_ops->task_free_security(p);
         free_uid(p->user);
+ if (unlikely(p->ptrace)) {
+ write_lock_irq(&tasklist_lock);
+ __ptrace_unlink(p);
+ write_unlock_irq(&tasklist_lock);
+ }
         BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
         unhash_process(p);
 
@@ -427,7 +432,7 @@
          * There are only two places where our children can be:
          *
          * - in our child list
- * - in the global ptrace list
+ * - in our ptraced child list
          *
          * Search them and reparent children.
          */
@@ -442,14 +447,22 @@
         read_unlock(&tasklist_lock);
 }
 
-static inline void zap_thread(task_t *p, task_t *father)
+static inline void zap_thread(task_t *p, task_t *father, int traced)
 {
- ptrace_unlink(p);
- list_del_init(&p->sibling);
- p->ptrace = 0;
+ /* If we were tracing the thread, release it; otherwise preserve the
+ ptrace links. */
+ if (unlikely(traced)) {
+ task_t *trace_task = p->parent;
+ __ptrace_unlink(p);
+ p->ptrace = 1;
+ __ptrace_link(p, trace_task);
+ } else {
+ p->ptrace = 0;
+ list_del_init(&p->sibling);
+ p->parent = p->real_parent;
+ list_add_tail(&p->sibling, &p->parent->children);
+ }
 
- p->parent = p->real_parent;
- list_add_tail(&p->sibling, &p->parent->children);
         if (p->state == TASK_ZOMBIE && p->exit_signal != -1)
                 do_notify_parent(p, p->exit_signal);
         /*
@@ -540,11 +553,11 @@
 
 zap_again:
         list_for_each_safe(_p, _n, &current->children)
- zap_thread(list_entry(_p,struct task_struct,sibling), current);
+ zap_thread(list_entry(_p,struct task_struct,sibling), current, 0);
         list_for_each_safe(_p, _n, &current->ptrace_children)
- zap_thread(list_entry(_p,struct task_struct,ptrace_list), current);
+ zap_thread(list_entry(_p,struct task_struct,ptrace_list), current, 1);
         /*
- * reparent_thread might drop the tasklist lock, thus we could
+ * zap_thread might drop the tasklist lock, thus we could
          * have new children queued back from the ptrace list into the
          * child list:
          */
@@ -715,7 +728,7 @@
                                 retval = p->pid;
                                 if (p->real_parent != p->parent) {
                                         write_lock_irq(&tasklist_lock);
- ptrace_unlink(p);
+ __ptrace_unlink(p);
                                         do_notify_parent(p, SIGCHLD);
                                         write_unlock_irq(&tasklist_lock);
                                 } else
--- linux/kernel/ptrace.c.orig Fri Sep 6 00:58:13 2002
+++ linux/kernel/ptrace.c Fri Sep 6 00:58:24 2002
@@ -29,7 +29,7 @@
         if (!list_empty(&child->ptrace_list))
                 BUG();
         if (child->parent == new_parent)
- BUG();
+ return;
         list_add(&child->ptrace_list, &child->parent->ptrace_children);
         REMOVE_LINKS(child);
         child->parent = new_parent;

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

This archive was generated by hypermail 2b29 : Sat Sep 07 2002 - 22:00:27 EST