UBUNTU: Ubuntu-2.6.38-12.51

[linux-flexiantxendom0-natty.git] / kernel / hung_task.c

diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 0c924de..53ead17 100644 (file)
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -72,7 +72,13 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 {
        unsigned long switch_count = t->nvcsw + t->nivcsw;
 
-       if (t->flags & PF_FROZEN)
+       /*
+        * Ensure the task is not frozen.
+        * Also, when a freshly created task is scheduled once, changes
+        * its state to TASK_UNINTERRUPTIBLE without having ever been
+        * switched out once, it musn't be checked.
+        */
+       if (unlikely(t->flags & PF_FROZEN || !switch_count))
                return;
 
        if (switch_count != t->last_switch_count) {
@@ -92,7 +98,7 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
        printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
                        " disables this message.\n");
        sched_show_task(t);
-       __debug_show_held_locks(t);
+       debug_show_held_locks(t);
 
        touch_nmi_watchdog();
 
@@ -105,7 +111,7 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
  * periodically exit the critical section and enter a new one.
  *
  * For preemptible RCU it is sufficient to call rcu_read_unlock in order
- * exit the grace period. For classic RCU, a reschedule is required.
+ * 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)
 {
@@ -138,7 +144,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
 
        rcu_read_lock();
        do_each_thread(g, t) {
-               if (!--max_count)
+               if (!max_count--)
                        goto unlock;
                if (!--batch_count) {
                        batch_count = HUNG_TASK_BATCHING;
@@ -165,12 +171,12 @@ static unsigned long timeout_jiffies(unsigned long timeout)
  * Process updating of timeout sysctl
  */
 int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
-                                 struct file *filp, void __user *buffer,
+                                 void __user *buffer,
                                  size_t *lenp, loff_t *ppos)
 {
        int ret;
 
-       ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+       ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 
        if (ret || !write)
                goto out;