1 files changed, 16 insertions, 6 deletions

diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index eb39a2775236..f7a9d1421078 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -254,7 +254,6 @@ void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
 {
         const unsigned cpu = safe_smp_processor_id();
         unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
-        int i = 11;
         unsigned used = 0;
 
         printk("\nCall Trace:\n");
@@ -275,11 +274,20 @@ void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
                         if (unwind_init_blocked(&info, tsk) == 0)
                                 unw_ret = show_trace_unwind(&info, NULL);
                 }
-                if (unw_ret > 0) {
-                        if (call_trace > 0)
+                if (unw_ret > 0 && !arch_unw_user_mode(&info)) {
+#ifdef CONFIG_STACK_UNWIND
+                        unsigned long rip = info.regs.rip;
+                        print_symbol("DWARF2 unwinder stuck at %s\n", rip);
+                        if (call_trace == 1) {
+                                printk("Leftover inexact backtrace:\n");
+                                stack = (unsigned long *)info.regs.rsp;
+                        } else if (call_trace > 1)
                                 return;
-                        printk("Legacy call trace:");
-                        i = 18;
+                        else
+                                printk("Full inexact backtrace again:\n");
+#else
+                        printk("Inexact backtrace:\n");
+#endif
                 }
         }
 
@@ -1118,8 +1126,10 @@ static int __init call_trace_setup(char *s)
                 call_trace = -1;
         else if (strcmp(s, "both") == 0)
                 call_trace = 0;
-        else if (strcmp(s, "new") == 0)
+        else if (strcmp(s, "newfallback") == 0)
                 call_trace = 1;
+        else if (strcmp(s, "new") == 0)
+                call_trace = 2;
         return 1;
 }
 __setup("call_trace=", call_trace_setup);