1 files changed, 42 insertions, 31 deletions

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 2bf8b55b91f8..0d4005dc06c5 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -100,13 +100,13 @@ int register_die_notifier(struct notifier_block *nb)
         vmalloc_sync_all();
         return atomic_notifier_chain_register(&i386die_chain, nb);
 }
-EXPORT_SYMBOL(register_die_notifier);
+EXPORT_SYMBOL(register_die_notifier); /* used modular by kdb */
 
 int unregister_die_notifier(struct notifier_block *nb)
 {
         return atomic_notifier_chain_unregister(&i386die_chain, nb);
 }
-EXPORT_SYMBOL(unregister_die_notifier);
+EXPORT_SYMBOL(unregister_die_notifier); /* used modular by kdb */
 
 static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
 {
@@ -187,10 +187,21 @@ static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
                         if (unwind_init_blocked(&info, task) == 0)
                                 unw_ret = show_trace_unwind(&info, log_lvl);
                 }
-                if (unw_ret > 0) {
-                        if (call_trace > 0)
+                if (unw_ret > 0 && !arch_unw_user_mode(&info)) {
+#ifdef CONFIG_STACK_UNWIND
+                        print_symbol("DWARF2 unwinder stuck at %s\n",
+                                     UNW_PC(&info));
+                        if (call_trace == 1) {
+                                printk("Leftover inexact backtrace:\n");
+                                if (UNW_SP(&info))
+                                        stack = (void *)UNW_SP(&info);
+                        } else if (call_trace > 1)
                                 return;
-                        printk("%sLegacy call trace:\n", log_lvl);
+                        else
+                                printk("Full inexact backtrace again:\n");
+#else
+                        printk("Inexact backtrace:\n");
+#endif
                 }
         }
 
@@ -324,35 +335,35 @@ void show_registers(struct pt_regs *regs)
 
 static void handle_BUG(struct pt_regs *regs)
 {
+        unsigned long eip = regs->eip;
         unsigned short ud2;
-        unsigned short line;
-        char *file;
-        char c;
-        unsigned long eip;
-
-        eip = regs->eip;
 
         if (eip < PAGE_OFFSET)
-                goto no_bug;
+                return;
         if (__get_user(ud2, (unsigned short __user *)eip))
-                goto no_bug;
+                return;
         if (ud2 != 0x0b0f)
-                goto no_bug;
-        if (__get_user(line, (unsigned short __user *)(eip + 2)))
-                goto bug;
-        if (__get_user(file, (char * __user *)(eip + 4)) ||
-                (unsigned long)file < PAGE_OFFSET || __get_user(c, file))
-                file = "<bad filename>";
+                return;
 
         printk(KERN_EMERG "------------[ cut here ]------------\n");
-        printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
 
-no_bug:
-        return;
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+        do {
+                unsigned short line;
+                char *file;
+                char c;
+
+                if (__get_user(line, (unsigned short __user *)(eip + 2)))
+                        break;
+                if (__get_user(file, (char * __user *)(eip + 4)) ||
+                    (unsigned long)file < PAGE_OFFSET || __get_user(c, file))
+                        file = "<bad filename>";
 
-        /* Here we know it was a BUG but file-n-line is unavailable */
-bug:
-        printk(KERN_EMERG "Kernel BUG\n");
+                printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
+                return;
+        } while (0);
+#endif
+        printk(KERN_EMERG "Kernel BUG at [verbose debug info unavailable]\n");
 }
 
 /* This is gone through when something in the kernel
@@ -442,11 +453,9 @@ void die(const char * str, struct pt_regs * regs, long err)
         if (in_interrupt())
                 panic("Fatal exception in interrupt");
 
-        if (panic_on_oops) {
-                printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
-                ssleep(5);
-                panic("Fatal exception");
-        }
+        if (panic_on_oops)
+                panic("Fatal exception: panic_on_oops");
+
         oops_exit();
         do_exit(SIGSEGV);
 }
@@ -1238,8 +1247,10 @@ 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") == 2)
+                call_trace = 2;
         return 1;
 }
 __setup("call_trace=", call_trace_setup);