+/*
+ * This must be called with current->sighand->siglock held.
+ *
+ * This should be the path for all ptrace stops.
+ * We always set current->last_siginfo while stopped here.
+ * That makes it a way to test a stopped process for
+ * being ptrace-stopped vs being job-control-stopped.
+ *
+ * If we actually decide not to stop at all because the tracer is gone,
+ * we leave nostop_code in current->exit_code.
+ */
+static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info)
+{
+ /*
+ * If there is a group stop in progress,
+ * we must participate in the bookkeeping.
+ */
+ if (current->signal->group_stop_count > 0)
+ --current->signal->group_stop_count;
+
+ current->last_siginfo = info;
+ current->exit_code = exit_code;
+
+ /* Let the debugger run. */
+ set_current_state(TASK_TRACED);
+ spin_unlock_irq(¤t->sighand->siglock);
+ read_lock(&tasklist_lock);
+ if (likely(current->ptrace & PT_PTRACED) &&
+ likely(current->parent != current->real_parent ||
+ !(current->ptrace & PT_ATTACHED)) &&
+ (likely(current->parent->signal != current->signal) ||
+ !unlikely(current->signal->flags & SIGNAL_GROUP_EXIT))) {
+ do_notify_parent_cldstop(current, current->parent,
+ CLD_TRAPPED);
+ read_unlock(&tasklist_lock);
+ schedule();
+ } else {
+ /*
+ * By the time we got the lock, our tracer went away.
+ * Don't stop here.
+ */
+ read_unlock(&tasklist_lock);
+ set_current_state(TASK_RUNNING);
+ current->exit_code = nostop_code;
+ }
+
+ /*
+ * We are back. Now reacquire the siglock before touching
+ * last_siginfo, so that we are sure to have synchronized with
+ * any signal-sending on another CPU that wants to examine it.
+ */
+ spin_lock_irq(¤t->sighand->siglock);
+ current->last_siginfo = NULL;
+
+ /*
+ * Queued signals ignored us while we were stopped for tracing.
+ * So check for any that we should take before resuming user mode.
+ */
+ recalc_sigpending();
+}
+
+void ptrace_notify(int exit_code)
+{
+ siginfo_t info;
+
+ BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+
+ memset(&info, 0, sizeof info);
+ info.si_signo = SIGTRAP;
+ info.si_code = exit_code;
+ info.si_pid = current->pid;
+ info.si_uid = current->uid;
+
+ /* Let the debugger run. */
+ spin_lock_irq(¤t->sighand->siglock);
+ ptrace_stop(exit_code, 0, &info);
+ spin_unlock_irq(¤t->sighand->siglock);
+}