Merge branch develop-3.10

[firefly-linux-kernel-4.4.55.git] / kernel / hung_task.c

diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index e972276f12ff7bd6726f654373938643fcdda60c..6df614912b9d40a9f77dd4fadc54af4fa1ca3ccb 100644 (file)
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -13,7 +13,7 @@
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/lockdep.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/sysctl.h>
 
 /*
@@ -108,8 +108,10 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 
        touch_nmi_watchdog();
 
-       if (sysctl_hung_task_panic)
+       if (sysctl_hung_task_panic) {
+               trigger_all_cpu_backtrace();
                panic("hung_task: blocked tasks");
+       }
 }
 
 /*
@@ -119,15 +121,20 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
  * For preemptible RCU it is sufficient to call rcu_read_unlock in order
  * to exit the grace period. For classic RCU, a reschedule is required.
  */
-static void rcu_lock_break(struct task_struct *g, struct task_struct *t)
+static bool rcu_lock_break(struct task_struct *g, struct task_struct *t)
 {
+       bool can_cont;
+
        get_task_struct(g);
        get_task_struct(t);
        rcu_read_unlock();
        cond_resched();
        rcu_read_lock();
+       can_cont = pid_alive(g) && pid_alive(t);
        put_task_struct(t);
        put_task_struct(g);
+
+       return can_cont;
 }
 
 /*
@@ -154,9 +161,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
                        goto unlock;
                if (!--batch_count) {
                        batch_count = HUNG_TASK_BATCHING;
-                       rcu_lock_break(g, t);
-                       /* Exit if t or g was unhashed during refresh. */
-                       if (t->state == TASK_DEAD || g->state == TASK_DEAD)
+                       if (!rcu_lock_break(g, t))
                                goto unlock;
                }
                /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */