1 files changed, 41 insertions, 7 deletions

diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 01b6522fd92b..6b682d86bddf 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -25,7 +25,22 @@ static DEFINE_PER_CPU(unsigned long, print_timestamp);
 static DEFINE_PER_CPU(struct task_struct *, watchdog_task);
 
 static int __read_mostly did_panic;
-unsigned long __read_mostly softlockup_thresh = 60;
+int __read_mostly softlockup_thresh = 60;
+
+/*
+ * Should we panic (and reboot, if panic_timeout= is set) when a
+ * soft-lockup occurs:
+ */
+unsigned int __read_mostly softlockup_panic =
+                                CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
+
+static int __init softlockup_panic_setup(char *str)
+{
+        softlockup_panic = simple_strtoul(str, NULL, 0);
+
+        return 1;
+}
+__setup("softlockup_panic=", softlockup_panic_setup);
 
 static int
 softlock_panic(struct notifier_block *this, unsigned long event, void *ptr)
@@ -49,12 +64,17 @@ static unsigned long get_timestamp(int this_cpu)
         return cpu_clock(this_cpu) >> 30LL;  /* 2^30 ~= 10^9 */
 }
 
-void touch_softlockup_watchdog(void)
+static void __touch_softlockup_watchdog(void)
 {
         int this_cpu = raw_smp_processor_id();
 
         __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu);
 }
+
+void touch_softlockup_watchdog(void)
+{
+        __raw_get_cpu_var(touch_timestamp) = 0;
+}
 EXPORT_SYMBOL(touch_softlockup_watchdog);
 
 void touch_all_softlockup_watchdogs(void)
@@ -79,8 +99,16 @@ void softlockup_tick(void)
         struct pt_regs *regs = get_irq_regs();
         unsigned long now;
 
+        /* Is detection switched off? */
+        if (!per_cpu(watchdog_task, this_cpu) || softlockup_thresh <= 0) {
+                /* Be sure we don't false trigger if switched back on */
+                if (touch_timestamp)
+                        per_cpu(touch_timestamp, this_cpu) = 0;
+                return;
+        }
+
         if (touch_timestamp == 0) {
-                touch_softlockup_watchdog();
+                __touch_softlockup_watchdog();
                 return;
         }
 
@@ -89,13 +117,13 @@ void softlockup_tick(void)
         /* report at most once a second */
         if ((print_timestamp >= touch_timestamp &&
                         print_timestamp < (touch_timestamp + 1)) ||
-                        did_panic || !per_cpu(watchdog_task, this_cpu)) {
+                        did_panic) {
                 return;
         }
 
         /* do not print during early bootup: */
         if (unlikely(system_state != SYSTEM_RUNNING)) {
-                touch_softlockup_watchdog();
+                __touch_softlockup_watchdog();
                 return;
         }
 
@@ -120,6 +148,9 @@ void softlockup_tick(void)
         else
                 dump_stack();
         spin_unlock(&print_lock);
+
+        if (softlockup_panic)
+                panic("softlockup: hung tasks");
 }
 
 /*
@@ -172,6 +203,9 @@ static void check_hung_task(struct task_struct *t, unsigned long now)
 
         t->last_switch_timestamp = now;
         touch_nmi_watchdog();
+
+        if (softlockup_panic)
+                panic("softlockup: blocked tasks");
 }
 
 /*
@@ -214,7 +248,7 @@ static int watchdog(void *__bind_cpu)
         sched_setscheduler(current, SCHED_FIFO, &param);
 
         /* initialize timestamp */
-        touch_softlockup_watchdog();
+        __touch_softlockup_watchdog();
 
         set_current_state(TASK_INTERRUPTIBLE);
         /*
@@ -223,7 +257,7 @@ static int watchdog(void *__bind_cpu)
          * debug-printout triggers in softlockup_tick().
          */
         while (!kthread_should_stop()) {
-                touch_softlockup_watchdog();
+                __touch_softlockup_watchdog();
                 schedule();
 
                 if (kthread_should_stop())