Merge branch 'linux-3.4.35' into rel-17

Bug 1243631

Change-Id: I915826047b2e20f0ad0a7d75df295c6cbf6e5b0a

1 files changed, 9 insertions, 10 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 1dd48f7e7d6f..563b7711d234 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -677,23 +677,17 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
  * No need to set need_resched since signal event passing
  * goes through ->blocked
  */
-void signal_wake_up(struct task_struct *t, int resume)
+void signal_wake_up_state(struct task_struct *t, unsigned int state)
 {
-	unsigned int mask;
-
 	set_tsk_thread_flag(t, TIF_SIGPENDING);
-
 	/*
-	 * For SIGKILL, we want to wake it up in the stopped/traced/killable
+	 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
 	 * case. We don't check t->state here because there is a race with it
 	 * executing another processor and just now entering stopped state.
 	 * By using wake_up_state, we ensure the process will wake up and
 	 * handle its death signal.
 	 */
-	mask = TASK_INTERRUPTIBLE;
-	if (resume)
-		mask |= TASK_WAKEKILL;
-	if (!wake_up_state(t, mask))
+	if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
 		kick_process(t);
 }
 
@@ -842,7 +836,7 @@ static void ptrace_trap_notify(struct task_struct *t)
 	assert_spin_locked(&t->sighand->siglock);
 
 	task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
-	signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
+	ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
 }
 
 /*
@@ -1808,6 +1802,10 @@ static inline int may_ptrace_stop(void)
 	 * If SIGKILL was already sent before the caller unlocked
 	 * ->siglock we must see ->core_state != NULL. Otherwise it
 	 * is safe to enter schedule().
+	 *
+	 * This is almost outdated, a task with the pending SIGKILL can't
+	 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
+	 * after SIGKILL was already dequeued.
 	 */
 	if (unlikely(current->mm->core_state) &&
 	    unlikely(current->mm == current->parent->mm))
@@ -1933,6 +1931,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
 		if (gstop_done)
 			do_notify_parent_cldstop(current, false, why);
 
+		/* tasklist protects us from ptrace_freeze_traced() */
 		__set_current_state(TASK_RUNNING);
 		if (clear_code)
 			current->exit_code = 0;