1 files changed, 20 insertions, 12 deletions

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 7e426459e60a..19db29f67558 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -16,6 +16,7 @@
 #include <linux/freezer.h>
 #include <linux/delay.h>
 #include <linux/workqueue.h>
+#include <linux/kmod.h>
 
 /* 
  * Timeout for stopping processes
@@ -53,11 +54,9 @@ static int try_to_freeze_tasks(bool user_only)
                          * It is "frozen enough".  If the task does wake
                          * up, it will immediately call try_to_freeze.
                          *
-                         * Because freeze_task() goes through p's
-                         * scheduler lock after setting TIF_FREEZE, it's
-                         * guaranteed that either we see TASK_RUNNING or
-                         * try_to_stop() after schedule() in ptrace/signal
-                         * stop sees TIF_FREEZE.
+                         * Because freeze_task() goes through p's scheduler lock, it's
+                         * guaranteed that TASK_STOPPED/TRACED -> TASK_RUNNING
+                         * transition can't race with task state testing here.
                          */
                         if (!task_is_stopped_or_traced(p) &&
                             !freezer_should_skip(p))
@@ -98,13 +97,15 @@ static int try_to_freeze_tasks(bool user_only)
                        elapsed_csecs / 100, elapsed_csecs % 100,
                        todo - wq_busy, wq_busy);
 
-                read_lock(&tasklist_lock);
-                do_each_thread(g, p) {
-                        if (!wakeup && !freezer_should_skip(p) &&
-                            p != current && freezing(p) && !frozen(p))
-                                sched_show_task(p);
-                } while_each_thread(g, p);
-                read_unlock(&tasklist_lock);
+                if (!wakeup) {
+                        read_lock(&tasklist_lock);
+                        do_each_thread(g, p) {
+                                if (p != current && !freezer_should_skip(p)
+                                    && freezing(p) && !frozen(p))
+                                        sched_show_task(p);
+                        } while_each_thread(g, p);
+                        read_unlock(&tasklist_lock);
+                }
         } else {
                 printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100,
                         elapsed_csecs % 100);
@@ -122,6 +123,10 @@ int freeze_processes(void)
 {
         int error;
 
+        error = __usermodehelper_disable(UMH_FREEZING);
+        if (error)
+                return error;
+
         if (!pm_freezing)
                 atomic_inc(&system_freezing_cnt);
 
@@ -130,6 +135,7 @@ int freeze_processes(void)
         error = try_to_freeze_tasks(true);
         if (!error) {
                 printk("done.");
+                __usermodehelper_set_disable_depth(UMH_DISABLED);
                 oom_killer_disable();
         }
         printk("\n");
@@ -187,6 +193,8 @@ void thaw_processes(void)
         } while_each_thread(g, p);
         read_unlock(&tasklist_lock);
 
+        usermodehelper_enable();
+
         schedule();
         printk("done.\n");
 }