Merge branch 'paul' (Fixups from Paul Gortmaker)

[linux-flexiantxendom0-3.2.10.git] / kernel / panic.c

diff --git a/kernel/panic.c b/kernel/panic.c
index 3e9037a..80aed44 100644 (file)
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -34,6 +34,7 @@ static int pause_on_oops_flag;
 static DEFINE_SPINLOCK(pause_on_oops_lock);
 
 int panic_timeout;
+EXPORT_SYMBOL_GPL(panic_timeout);
 
 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
 
@@ -48,6 +49,15 @@ static long no_blink(int state)
 long (*panic_blink)(int state);
 EXPORT_SYMBOL(panic_blink);
 
+/*
+ * Stop ourself in panic -- architecture code may override this
+ */
+void __weak panic_smp_self_stop(void)
+{
+       while (1)
+               cpu_relax();
+}
+
 /**
  *     panic - halt the system
  *     @fmt: The text string to print
@@ -56,8 +66,9 @@ EXPORT_SYMBOL(panic_blink);
  *
  *     This function never returns.
  */
-NORET_TYPE void panic(const char * fmt, ...)
+void panic(const char *fmt, ...)
 {
+       static DEFINE_SPINLOCK(panic_lock);
        static char buf[1024];
        va_list args;
        long i, i_next = 0;
@@ -67,8 +78,14 @@ NORET_TYPE void panic(const char * fmt, ...)
         * It's possible to come here directly from a panic-assertion and
         * not have preempt disabled. Some functions called from here want
         * preempt to be disabled. No point enabling it later though...
+        *
+        * Only one CPU is allowed to execute the panic code from here. For
+        * multiple parallel invocations of panic, all other CPUs either
+        * stop themself or will wait until they are stopped by the 1st CPU
+        * with smp_send_stop().
         */
-       preempt_disable();
+       if (!spin_trylock(&panic_lock))
+               panic_smp_self_stop();
 
        console_verbose();
        bust_spinlocks(1);
@@ -77,7 +94,11 @@ NORET_TYPE void panic(const char * fmt, ...)
        va_end(args);
        printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
 #ifdef CONFIG_DEBUG_BUGVERBOSE
-       dump_stack();
+       /*
+        * Avoid nested stack-dumping if a panic occurs during oops processing
+        */
+       if (!oops_in_progress)
+               dump_stack();
 #endif
 
        /*
@@ -118,6 +139,8 @@ NORET_TYPE void panic(const char * fmt, ...)
                        }
                        mdelay(PANIC_TIMER_STEP);
                }
+       }
+       if (panic_timeout != 0) {
                /*
                 * This will not be a clean reboot, with everything
                 * shutting down.  But if there is a chance of
@@ -174,6 +197,7 @@ static const struct tnt tnts[] = {
        { TAINT_WARN,                   'W', ' ' },
        { TAINT_CRAP,                   'C', ' ' },
        { TAINT_FIRMWARE_WORKAROUND,    'I', ' ' },
+       { TAINT_OOT_MODULE,             'O', ' ' },
 };
 
 /**
@@ -191,6 +215,7 @@ static const struct tnt tnts[] = {
  *  'W' - Taint on warning.
  *  'C' - modules from drivers/staging are loaded.
  *  'I' - Working around severe firmware bug.
+ *  'O' - Out-of-tree module has been loaded.
  *
  *     The string is overwritten by the next call to print_tainted().
  */
@@ -232,11 +257,20 @@ void add_taint(unsigned flag)
         * Can't trust the integrity of the kernel anymore.
         * We don't call directly debug_locks_off() because the issue
         * is not necessarily serious enough to set oops_in_progress to 1
-        * Also we want to keep up lockdep for staging development and
-        * post-warning case.
+        * Also we want to keep up lockdep for staging/out-of-tree
+        * development and post-warning case.
         */
-       if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
-               printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
+       switch (flag) {
+       case TAINT_CRAP:
+       case TAINT_OOT_MODULE:
+       case TAINT_WARN:
+       case TAINT_FIRMWARE_WORKAROUND:
+               break;
+
+       default:
+               if (__debug_locks_off())
+                       printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
+       }
 
        set_bit(flag, &tainted_mask);
 }
@@ -338,7 +372,7 @@ static int init_oops_id(void)
 }
 late_initcall(init_oops_id);
 
-static void print_oops_end_marker(void)
+void print_oops_end_marker(void)
 {
        init_oops_id();
        printk(KERN_WARNING "---[ end trace %016llx ]---\n",
@@ -432,3 +466,13 @@ EXPORT_SYMBOL(__stack_chk_fail);
 
 core_param(panic, panic_timeout, int, 0644);
 core_param(pause_on_oops, pause_on_oops, int, 0644);
+
+static int __init oops_setup(char *s)
+{
+       if (!s)
+               return -EINVAL;
+       if (!strcmp(s, "panic"))
+               panic_on_oops = 1;
+       return 0;
+}
+early_param("oops", oops_setup);