[libata] sata_fsl: fix the controller operating mode

[pandora-kernel.git] / kernel / panic.c

diff --git a/kernel/panic.c b/kernel/panic.c
index 3458469..80aed44 100644 (file)
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -49,6 +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
@@ -57,8 +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;
@@ -68,8 +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);
@@ -78,7 +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
 
        /*