1 files changed, 31 insertions, 24 deletions

diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 0d65b22f229c..a1641ffdffcf 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -30,9 +30,9 @@
 #include <linux/kprobes.h>
 #include <linux/kexec.h>
 #include <linux/unwind.h>
+#include <linux/uaccess.h>
 
 #include <asm/system.h>
-#include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/atomic.h>
 #include <asm/debugreg.h>
@@ -108,7 +108,7 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
         preempt_enable_no_resched();
 }
 
-static int kstack_depth_to_print = 12;
+int kstack_depth_to_print = 12;
 #ifdef CONFIG_STACK_UNWIND
 static int call_trace = 1;
 #else
@@ -225,16 +225,25 @@ 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;
+        unsigned long sp = UNW_SP(info);
 
+        if (arch_unw_user_mode(info))
+                return -1;
         while (unwind(info) == 0 && UNW_PC(info)) {
                 n++;
                 oad->ops->address(oad->data, UNW_PC(info));
                 if (arch_unw_user_mode(info))
                         break;
+                if ((sp & ~(PAGE_SIZE - 1)) == (UNW_SP(info) & ~(PAGE_SIZE - 1))
+                    && sp > UNW_SP(info))
+                        break;
+                sp = UNW_SP(info);
         }
         return n;
 }
 
+#define MSG(txt) ops->warning(data, txt)
+
 /*
  * x86-64 can have upto three kernel stacks: 
  * process stack
@@ -248,11 +257,12 @@ 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;
 
@@ -268,28 +278,30 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
                         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);
+                        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",
+                                ops->warning_symbol(data,
+                                             "DWARF2 unwinder stuck at %s",
                                              UNW_PC(&info));
                                 if ((long)UNW_SP(&info) < 0) {
-                                        ops->warning(data, "Leftover inexact backtrace:\n");
+                                        MSG("Leftover inexact backtrace:");
                                         stack = (unsigned long *)UNW_SP(&info);
                                         if (!stack)
-                                                return;
+                                                goto out;
                                 } else
-                                        ops->warning(data, "Full inexact backtrace again:\n");
+                                        MSG("Full inexact backtrace again:");
                         } else if (call_trace >= 1)
-                                return;
+                                goto out;
                         else
-                                ops->warning(data, "Full inexact backtrace again:\n");
+                                MSG("Full inexact backtrace again:");
                 } else
-                        ops->warning(data, "Inexact backtrace:\n");
+                        MSG("Inexact backtrace:");
         }
         if (!stack) {
                 unsigned long dummy;
@@ -297,12 +309,6 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
                 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 +318,9 @@ 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 \
@@ -380,6 +386,8 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
         tinfo = current_thread_info();
         HANDLE_STACK (valid_stack_ptr(tinfo, stack));
 #undef HANDLE_STACK
+out:
+        put_cpu();
 }
 EXPORT_SYMBOL(dump_trace);
 
@@ -786,8 +794,7 @@ 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");