[PATCH] TLB shootdown infrastructure in 2.5

It looks like a race betwen exec_mmap and access_process_vm in
proc_pid_cmdline (or any other procfs functions that uses
access_process_vm).

fs/exec.c

@@ -396,11 +396,14 @@ static int exec_mmap(void)
 	struct mm_struct * mm, * old_mm;
 
 	old_mm = current->mm;
+	task_lock(current);
 	if (old_mm && atomic_read(&old_mm->mm_users) == 1) {
 		mm_release();
 		exit_mmap(old_mm);
+		task_unlock(current);
 		return 0;
 	}
+	task_unlock(current);
 
 	mm = mm_alloc();
 	if (mm) {