1 files changed, 31 insertions, 9 deletions

diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 6848828b962e..19e5e9eba546 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -2,8 +2,8 @@
  *  arch/s390/kernel/debug.c
  *   S/390 debug facility
  *
- *    Copyright (C) 1999, 2000 IBM Deutschland Entwicklung GmbH,
- *                             IBM Corporation
+ *    Copyright IBM Corp. 1999, 2012
+ *
  *    Author(s): Michael Holzheu (holzheu@de.ibm.com),
  *               Holger Smolinski (Holger.Smolinski@de.ibm.com)
  *
@@ -167,6 +167,7 @@ static debug_info_t *debug_area_last = NULL;
 static DEFINE_MUTEX(debug_mutex);
 
 static int initialized;
+static int debug_critical;
 
 static const struct file_operations debug_file_ops = {
         .owner   = THIS_MODULE,
@@ -932,6 +933,11 @@ debug_stop_all(void)
 }
 
 
+void debug_set_critical(void)
+{
+        debug_critical = 1;
+}
+
 /*
  * debug_event_common:
  * - write debug entry with given size
@@ -945,7 +951,11 @@ debug_event_common(debug_info_t * id, int level, const void *buf, int len)
 
         if (!debug_active || !id->areas)
                 return NULL;
-        spin_lock_irqsave(&id->lock, flags);
+        if (debug_critical) {
+                if (!spin_trylock_irqsave(&id->lock, flags))
+                        return NULL;
+        } else
+                spin_lock_irqsave(&id->lock, flags);
         active = get_active_entry(id);
         memset(DEBUG_DATA(active), 0, id->buf_size);
         memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
@@ -968,7 +978,11 @@ debug_entry_t
 
         if (!debug_active || !id->areas)
                 return NULL;
-        spin_lock_irqsave(&id->lock, flags);
+        if (debug_critical) {
+                if (!spin_trylock_irqsave(&id->lock, flags))
+                        return NULL;
+        } else
+                spin_lock_irqsave(&id->lock, flags);
         active = get_active_entry(id);
         memset(DEBUG_DATA(active), 0, id->buf_size);
         memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
@@ -1013,7 +1027,11 @@ debug_sprintf_event(debug_info_t* id, int level,char *string,...)
                 return NULL;
         numargs=debug_count_numargs(string);
 
-        spin_lock_irqsave(&id->lock, flags);
+        if (debug_critical) {
+                if (!spin_trylock_irqsave(&id->lock, flags))
+                        return NULL;
+        } else
+                spin_lock_irqsave(&id->lock, flags);
         active = get_active_entry(id);
         curr_event=(debug_sprintf_entry_t *) DEBUG_DATA(active);
         va_start(ap,string);
@@ -1047,7 +1065,11 @@ debug_sprintf_exception(debug_info_t* id, int level,char *string,...)
 
         numargs=debug_count_numargs(string);
 
-        spin_lock_irqsave(&id->lock, flags);
+        if (debug_critical) {
+                if (!spin_trylock_irqsave(&id->lock, flags))
+                        return NULL;
+        } else
+                spin_lock_irqsave(&id->lock, flags);
         active = get_active_entry(id);
         curr_event=(debug_sprintf_entry_t *)DEBUG_DATA(active);
         va_start(ap,string);
@@ -1428,10 +1450,10 @@ debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
         rc += sprintf(out_buf + rc, "| ");
         for (i = 0; i < id->buf_size; i++) {
                 unsigned char c = in_buf[i];
-                if (!isprint(c))
-                        rc += sprintf(out_buf + rc, ".");
-                else
+                if (isascii(c) && isprint(c))
                         rc += sprintf(out_buf + rc, "%c", c);
+                else
+                        rc += sprintf(out_buf + rc, ".");
         }
         rc += sprintf(out_buf + rc, "\n");
         return rc;