1 files changed, 25 insertions, 114 deletions

diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 0d65b22f229c..09d2e8a10a49 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -30,9 +30,10 @@
 #include <linux/kprobes.h>
 #include <linux/kexec.h>
 #include <linux/unwind.h>
+#include <linux/uaccess.h>
+#include <linux/bug.h>
 
 #include <asm/system.h>
-#include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/atomic.h>
 #include <asm/debugreg.h>
@@ -108,12 +109,7 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
         preempt_enable_no_resched();
 }
 
-static int kstack_depth_to_print = 12;
-#ifdef CONFIG_STACK_UNWIND
-static int call_trace = 1;
-#else
-#define call_trace (-1)
-#endif
+int kstack_depth_to_print = 12;
 
 #ifdef CONFIG_KALLSYMS
 void printk_address(unsigned long address)
@@ -216,24 +212,7 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
         return NULL;
 }
 
-struct ops_and_data {
-        struct stacktrace_ops *ops;
-        void *data;
-};
-
-static int dump_trace_unwind(struct unwind_frame_info *info, void *context)
-{
-        struct ops_and_data *oad = (struct ops_and_data *)context;
-        int n = 0;
-
-        while (unwind(info) == 0 && UNW_PC(info)) {
-                n++;
-                oad->ops->address(oad->data, UNW_PC(info));
-                if (arch_unw_user_mode(info))
-                        break;
-        }
-        return n;
-}
+#define MSG(txt) ops->warning(data, txt)
 
 /*
  * x86-64 can have upto three kernel stacks: 
@@ -248,61 +227,24 @@ static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
         return p > t && p < t + THREAD_SIZE - 3;
 }
 
-void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * stack,
+void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
+                unsigned long *stack,
                 struct stacktrace_ops *ops, void *data)
 {
-        const unsigned cpu = smp_processor_id();
-        unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
+        const unsigned cpu = get_cpu();
+        unsigned long *irqstack_end = (unsigned long*)cpu_pda(cpu)->irqstackptr;
         unsigned used = 0;
         struct thread_info *tinfo;
 
         if (!tsk)
                 tsk = current;
 
-        if (call_trace >= 0) {
-                int unw_ret = 0;
-                struct unwind_frame_info info;
-                struct ops_and_data oad = { .ops = ops, .data = data };
-
-                if (regs) {
-                        if (unwind_init_frame_info(&info, tsk, regs) == 0)
-                                unw_ret = dump_trace_unwind(&info, &oad);
-                } else if (tsk == current)
-                        unw_ret = unwind_init_running(&info, dump_trace_unwind, &oad);
-                else {
-                        if (unwind_init_blocked(&info, tsk) == 0)
-                                unw_ret = dump_trace_unwind(&info, &oad);
-                }
-                if (unw_ret > 0) {
-                        if (call_trace == 1 && !arch_unw_user_mode(&info)) {
-                                ops->warning_symbol(data, "DWARF2 unwinder stuck at %s\n",
-                                             UNW_PC(&info));
-                                if ((long)UNW_SP(&info) < 0) {
-                                        ops->warning(data, "Leftover inexact backtrace:\n");
-                                        stack = (unsigned long *)UNW_SP(&info);
-                                        if (!stack)
-                                                return;
-                                } else
-                                        ops->warning(data, "Full inexact backtrace again:\n");
-                        } else if (call_trace >= 1)
-                                return;
-                        else
-                                ops->warning(data, "Full inexact backtrace again:\n");
-                } else
-                        ops->warning(data, "Inexact backtrace:\n");
-        }
         if (!stack) {
                 unsigned long dummy;
                 stack = &dummy;
                 if (tsk && tsk != current)
                         stack = (unsigned long *)tsk->thread.rsp;
         }
-        /*
-         * Align the stack pointer on word boundary, later loops
-         * rely on that (and corruption / debug info bugs can cause
-         * unaligned values here):
-         */
-        stack = (unsigned long *)((unsigned long)stack & ~(sizeof(long)-1));
 
         /*
          * Print function call entries within a stack. 'cond' is the
@@ -312,9 +254,9 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
 #define HANDLE_STACK(cond) \
         do while (cond) { \
                 unsigned long addr = *stack++; \
-                if (oops_in_progress ?          \
-                        __kernel_text_address(addr) : \
-                        kernel_text_address(addr)) { \
+                /* Use unlocked access here because except for NMIs     \
+                   we should be already protected against module unloads */ \
+                if (__kernel_text_address(addr)) { \
                         /* \
                          * If the address is either in the text segment of the \
                          * kernel, or in the region which contains vmalloc'ed \
@@ -377,9 +319,10 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
         /*
          * This handles the process stack:
          */
-        tinfo = current_thread_info();
+        tinfo = task_thread_info(tsk);
         HANDLE_STACK (valid_stack_ptr(tinfo, stack));
 #undef HANDLE_STACK
+        put_cpu();
 }
 EXPORT_SYMBOL(dump_trace);
 
@@ -516,30 +459,15 @@ bad:
         printk("\n");
 }       
 
-void handle_BUG(struct pt_regs *regs)
-{ 
-        struct bug_frame f;
-        long len;
-        const char *prefix = "";
+int is_valid_bugaddr(unsigned long rip)
+{
+        unsigned short ud2;
 
-        if (user_mode(regs))
-                return; 
-        if (__copy_from_user(&f, (const void __user *) regs->rip,
-                             sizeof(struct bug_frame)))
-                return; 
-        if (f.filename >= 0 ||
-            f.ud2[0] != 0x0f || f.ud2[1] != 0x0b) 
-                return;
-        len = __strnlen_user((char *)(long)f.filename, PATH_MAX) - 1;
-        if (len < 0 || len >= PATH_MAX)
-                f.filename = (int)(long)"unmapped filename";
-        else if (len > 50) {
-                f.filename += len - 50;
-                prefix = "...";
-        }
-        printk("----------- [cut here ] --------- [please bite here ] ---------\n");
-        printk(KERN_ALERT "Kernel BUG at %s%.50s:%d\n", prefix, (char *)(long)f.filename, f.line);
-} 
+        if (__copy_from_user(&ud2, (const void __user *) rip, sizeof(ud2)))
+                return 0;
+
+        return ud2 == 0x0b0f;
+}
 
 #ifdef CONFIG_BUG
 void out_of_line_bug(void)
@@ -619,7 +547,9 @@ void die(const char * str, struct pt_regs * regs, long err)
 {
         unsigned long flags = oops_begin();
 
-        handle_BUG(regs);
+        if (!user_mode(regs))
+                report_bug(regs->rip);
+
         __die(str, regs, err);
         oops_end(flags);
         do_exit(SIGSEGV); 
@@ -786,8 +716,7 @@ mem_parity_error(unsigned char reason, struct pt_regs * regs)
 {
         printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
                 reason);
-        printk(KERN_EMERG "You probably have a hardware problem with your "
-                "RAM chips\n");
+        printk(KERN_EMERG "You have some hardware problem, likely on the PCI bus.\n");
 
         if (panic_on_unrecovered_nmi)
                 panic("NMI: Not continuing");
@@ -1193,21 +1122,3 @@ static int __init kstack_setup(char *s)
         return 0;
 }
 early_param("kstack", kstack_setup);
-
-#ifdef CONFIG_STACK_UNWIND
-static int __init call_trace_setup(char *s)
-{
-        if (!s)
-                return -EINVAL;
-        if (strcmp(s, "old") == 0)
-                call_trace = -1;
-        else if (strcmp(s, "both") == 0)
-                call_trace = 0;
-        else if (strcmp(s, "newfallback") == 0)
-                call_trace = 1;
-        else if (strcmp(s, "new") == 0)
-                call_trace = 2;
-        return 0;
-}
-early_param("call_trace", call_trace_setup);
-#endif