2 files changed, 26 insertions, 19 deletions

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 7c2118f9597f..f1d0b345c9ba 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -75,22 +75,15 @@ void refrigerator(void)
         __set_current_state(save);
 }
 
-static void fake_signal_wake_up(struct task_struct *p, int resume)
+static void fake_signal_wake_up(struct task_struct *p)
 {
         unsigned long flags;
 
         spin_lock_irqsave(&p->sighand->siglock, flags);
-        signal_wake_up(p, resume);
+        signal_wake_up(p, 0);
         spin_unlock_irqrestore(&p->sighand->siglock, flags);
 }
 
-static void send_fake_signal(struct task_struct *p)
-{
-        if (task_is_stopped(p))
-                force_sig_specific(SIGSTOP, p);
-        fake_signal_wake_up(p, task_is_stopped(p));
-}
-
 static int has_mm(struct task_struct *p)
 {
         return (p->mm && !(p->flags & PF_BORROWED_MM));
@@ -121,7 +114,7 @@ static int freeze_task(struct task_struct *p, int with_mm_only)
         if (freezing(p)) {
                 if (has_mm(p)) {
                         if (!signal_pending(p))
-                                fake_signal_wake_up(p, 0);
+                                fake_signal_wake_up(p);
                 } else {
                         if (with_mm_only)
                                 ret = 0;
@@ -135,7 +128,7 @@ static int freeze_task(struct task_struct *p, int with_mm_only)
                 } else {
                         if (has_mm(p)) {
                                 set_freeze_flag(p);
-                                send_fake_signal(p);
+                                fake_signal_wake_up(p);
                         } else {
                                 if (with_mm_only) {
                                         ret = 0;
@@ -182,15 +175,17 @@ static int try_to_freeze_tasks(int freeze_user_space)
                         if (frozen(p) || !freezeable(p))
                                 continue;
 
-                        if (task_is_traced(p) && frozen(p->parent)) {
-                                cancel_freezing(p);
-                                continue;
-                        }
-
                         if (!freeze_task(p, freeze_user_space))
                                 continue;
 
-                        if (!freezer_should_skip(p))
+                        /*
+                         * Now that we've done set_freeze_flag, don't
+                         * perturb a task in TASK_STOPPED or TASK_TRACED.
+                         * It is "frozen enough".  If the task does wake
+                         * up, it will immediately call try_to_freeze.
+                         */
+                        if (!task_is_stopped_or_traced(p) &&
+                            !freezer_should_skip(p))
                                 todo++;
                 } while_each_thread(g, p);
                 read_unlock(&tasklist_lock);
diff --git a/kernel/signal.c b/kernel/signal.c
index 84917fe507f7..6af1210092c3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1623,7 +1623,6 @@ static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
         /* Let the debugger run.  */
         __set_current_state(TASK_TRACED);
         spin_unlock_irq(&current->sighand->siglock);
-        try_to_freeze();
         read_lock(&tasklist_lock);
         if (!unlikely(killed) && may_ptrace_stop()) {
                 do_notify_parent_cldstop(current, CLD_TRAPPED);
@@ -1641,6 +1640,13 @@ static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
         }
 
         /*
+         * While in TASK_TRACED, we were considered "frozen enough".
+         * Now that we woke up, it's crucial if we're supposed to be
+         * frozen that we freeze now before running anything substantial.
+         */
+        try_to_freeze();
+
+        /*
          * 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.
@@ -1757,9 +1763,15 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
         sigset_t *mask = &current->blocked;
         int signr = 0;
 
+relock:
+        /*
+         * We'll jump back here after any time we were stopped in TASK_STOPPED.
+         * While in TASK_STOPPED, we were considered "frozen enough".
+         * Now that we woke up, it's crucial if we're supposed to be
+         * frozen that we freeze now before running anything substantial.
+         */
         try_to_freeze();
 
-relock:
         spin_lock_irq(&current->sighand->siglock);
         for (;;) {
                 struct k_sigaction *ka;