diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index f1ec129..3f89187 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -607,7 +607,7 @@
 	 */
  	list_for_each_safe(this, next, &current->children) {
 		p = list_entry(this, struct task_struct, sibling);
-		if (p->mm != mm)
+		if (p->tgid != child->tgid)
 			continue;
 		if (thread_matches(p, addr)) {
 			child = p;