1 files changed, 33 insertions, 13 deletions

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 286584667865..78464097470a 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -93,6 +93,7 @@ asmlinkage void spurious_interrupt_bug(void);
 asmlinkage void machine_check(void);
 
 static int kstack_depth_to_print = 24;
+static int call_trace = 1;
 ATOMIC_NOTIFIER_HEAD(i386die_chain);
 
 int register_die_notifier(struct notifier_block *nb)
@@ -171,40 +172,47 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
         return ebp;
 }
 
-static asmlinkage void show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)
+static asmlinkage int show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)
 {
+        int n = 0;
         int printed = 0; /* nr of entries already printed on current line */
 
         while (unwind(info) == 0 && UNW_PC(info)) {
+                ++n;
                 printed = print_addr_and_symbol(UNW_PC(info), log_lvl, printed);
                 if (arch_unw_user_mode(info))
                         break;
         }
         if (printed)
                 printk("\n");
+        return n;
 }
 
 static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
                                unsigned long *stack, char *log_lvl)
 {
         unsigned long ebp;
-        struct unwind_frame_info info;
 
         if (!task)
                 task = current;
 
-        if (regs) {
-                if (unwind_init_frame_info(&info, task, regs) == 0) {
-                        show_trace_unwind(&info, log_lvl);
-                        return;
+        if (call_trace >= 0) {
+                int unw_ret = 0;
+                struct unwind_frame_info info;
+
+                if (regs) {
+                        if (unwind_init_frame_info(&info, task, regs) == 0)
+                                unw_ret = show_trace_unwind(&info, log_lvl);
+                } else if (task == current)
+                        unw_ret = unwind_init_running(&info, show_trace_unwind, log_lvl);
+                else {
+                        if (unwind_init_blocked(&info, task) == 0)
+                                unw_ret = show_trace_unwind(&info, log_lvl);
                 }
-        } else if (task == current) {
-                if (unwind_init_running(&info, show_trace_unwind, log_lvl) == 0)
-                        return;
-        } else {
-                if (unwind_init_blocked(&info, task) == 0) {
-                        show_trace_unwind(&info, log_lvl);
-                        return;
+                if (unw_ret > 0) {
+                        if (call_trace > 0)
+                                return;
+                        printk("%sLegacy call trace:\n", log_lvl);
                 }
         }
 
@@ -1245,3 +1253,15 @@ static int __init kstack_setup(char *s)
         return 1;
 }
 __setup("kstack=", kstack_setup);
+
+static int __init call_trace_setup(char *s)
+{
+        if (strcmp(s, "old") == 0)
+                call_trace = -1;
+        else if (strcmp(s, "both") == 0)
+                call_trace = 0;
+        else if (strcmp(s, "new") == 0)
+                call_trace = 1;
+        return 1;
+}
+__setup("call_trace=", call_trace_setup);