diff -urN 2.3.18ac7/include/linux/sched.h 2.3.18ac7-nr_threads/include/linux/sched.h
--- 2.3.18ac7/include/linux/sched.h	Tue Sep 21 16:46:50 1999
+++ 2.3.18ac7-nr_threads/include/linux/sched.h	Wed Sep 22 15:31:53 1999
@@ -825,8 +825,8 @@
 extern inline void unhash_process(struct task_struct *p)
 {
 	if (task_on_runqueue(p)) BUG();
-	nr_threads--;
 	write_lock_irq(&tasklist_lock);
+	nr_threads--;
 	unhash_pid(p);
 	REMOVE_LINKS(p);
 	write_unlock_irq(&tasklist_lock);
diff -urN 2.3.18ac7/kernel/fork.c 2.3.18ac7-nr_threads/kernel/fork.c
--- 2.3.18ac7/kernel/fork.c	Tue Sep 21 16:46:51 1999
+++ 2.3.18ac7-nr_threads/kernel/fork.c	Wed Sep 22 15:36:40 1999
@@ -617,8 +617,9 @@
 	}
 
 	/*
-	 * Counter atomicity is protected by
-	 * the kernel lock
+	 * Counter increases are protected by
+	 * the kernel lock so nr_threads can't
+	 * increase under us (but it may decrease).
 	 */
 	if (nr_threads >= max_threads)
 		goto bad_fork_cleanup_count;
@@ -718,9 +719,9 @@
 	write_lock_irq(&tasklist_lock);
 	SET_LINKS(p);
 	hash_pid(p);
+	nr_threads++;
 	write_unlock_irq(&tasklist_lock);
 
-	nr_threads++;
 	wake_up_process(p);		/* do this last */
 	++total_forks;
 
@@ -742,8 +743,6 @@
 		__MOD_DEC_USE_COUNT(p->exec_domain->module);
 	if (p->binfmt && p->binfmt->module)
 		__MOD_DEC_USE_COUNT(p->binfmt->module);
-
-	nr_threads--;
 bad_fork_cleanup_count:
 	if (p->user)
 		free_uid(p);