2 files changed, 35 insertions, 13 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e7910f8b4fcc..40db7dd1d92a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -416,8 +416,8 @@ and is between 256 and 4096 characters. It is defined in the file
                         [SPARC64] tick
                         [X86-64] hpet,tsc
 
-        code_bytes      [IA32] How many bytes of object code to print in an
-                        oops report.
+        code_bytes      [IA32/X86_64] How many bytes of object code to print
+                        in an oops report.
                         Range: 0 - 8192
                         Default: 64
 
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 304ca6b4a1ca..0bba7924604e 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -74,6 +74,8 @@ asmlinkage void alignment_check(void);
 asmlinkage void machine_check(void);
 asmlinkage void spurious_interrupt_bug(void);
 
+static unsigned int code_bytes = 64;
+
 static inline void conditional_sti(struct pt_regs *regs)
 {
         if (regs->flags & X86_EFLAGS_IF)
@@ -459,12 +461,15 @@ EXPORT_SYMBOL(dump_stack);
 void show_registers(struct pt_regs *regs)
 {
         int i;
-        int in_kernel = !user_mode(regs);
         unsigned long sp;
         const int cpu = smp_processor_id();
         struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+        u8 *ip;
+        unsigned int code_prologue = code_bytes * 43 / 64;
+        unsigned int code_len = code_bytes;
 
         sp = regs->sp;
+        ip = (u8 *) regs->ip - code_prologue;
         printk("CPU %d ", cpu);
         __show_regs(regs);
         printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
@@ -474,22 +479,28 @@ void show_registers(struct pt_regs *regs)
          * When in-kernel, we also print out the stack and code at the
          * time of the fault..
          */
-        if (in_kernel) {
+        if (!user_mode(regs)) {
+                unsigned char c;
                 printk("Stack: ");
                 _show_stack(NULL, regs, (unsigned long *)sp, regs->bp);
+                printk("\n");
 
-                printk("\nCode: ");
-                if (regs->ip < PAGE_OFFSET)
-                        goto bad;
-
-                for (i=0; i<20; i++) {
-                        unsigned char c;
-                        if (__get_user(c, &((unsigned char*)regs->ip)[i])) {
-bad:
+                printk(KERN_EMERG "Code: ");
+                if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
+                        /* try starting at RIP */
+                        ip = (u8 *) regs->ip;
+                        code_len = code_len - code_prologue + 1;
+                }
+                for (i = 0; i < code_len; i++, ip++) {
+                        if (ip < (u8 *)PAGE_OFFSET ||
+                                        probe_kernel_address(ip, c)) {
                                 printk(" Bad RIP value.");
                                 break;
                         }
-                        printk("%02x ", c);
+                        if (ip == (u8 *)regs->ip)
+                                printk("<%02x> ", c);
+                        else
+                                printk("%02x ", c);
                 }
         }
         printk("\n");
@@ -1164,3 +1175,14 @@ static int __init kstack_setup(char *s)
         return 0;
 }
 early_param("kstack", kstack_setup);
+
+
+static int __init code_bytes_setup(char *s)
+{
+        code_bytes = simple_strtoul(s, NULL, 0);
+        if (code_bytes > 8192)
+                code_bytes = 8192;
+
+        return 1;
+}
+__setup("code_bytes=", code_bytes_setup);