1 files changed, 79 insertions, 68 deletions

diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index f6ccf155e3e..65a37f52c56 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -120,95 +120,106 @@ int printk_address(unsigned long address)
 } 
 #endif
 
-unsigned long *in_exception_stack(int cpu, unsigned long stack) 
-{ 
-	int k;
+static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
+					unsigned *usedp, const char **idp)
+{
+	static const char ids[N_EXCEPTION_STACKS][8] = {
+		[DEBUG_STACK - 1] = "#DB",
+		[NMI_STACK - 1] = "NMI",
+		[DOUBLEFAULT_STACK - 1] = "#DF",
+		[STACKFAULT_STACK - 1] = "#SS",
+		[MCE_STACK - 1] = "#MC",
+	};
+	unsigned k;
+
 	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
-		struct tss_struct *tss = &per_cpu(init_tss, cpu);
-		unsigned long start = tss->ist[k] - EXCEPTION_STKSZ;
+		unsigned long end;
 
-		if (stack >= start && stack < tss->ist[k])
-			return (unsigned long *)tss->ist[k];
+		end = per_cpu(init_tss, cpu).ist[k];
+		if (stack >= end)
+			continue;
+		if (stack >= end - EXCEPTION_STKSZ) {
+			if (*usedp & (1U << k))
+				break;
+			*usedp |= 1U << k;
+			*idp = ids[k];
+			return (unsigned long *)end;
+		}
 	}
 	return NULL;
-} 
+}
 
 /*
  * x86-64 can have upto three kernel stacks: 
  * process stack
  * interrupt stack
- * severe exception (double fault, nmi, stack fault) hardware stack
- * Check and process them in order.
+ * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  */
 
 void show_trace(unsigned long *stack)
 {
 	unsigned long addr;
-	unsigned long *irqstack, *irqstack_end, *estack_end;
-	const int cpu = safe_smp_processor_id();
+	const unsigned cpu = safe_smp_processor_id();
+	unsigned long *irqstack_end = (unsigned long *)cpu_pda[cpu].irqstackptr;
 	int i;
+	unsigned used = 0;
 
 	printk("\nCall Trace:");
-	i = 0; 
-	
-	estack_end = in_exception_stack(cpu, (unsigned long)stack); 
-	if (estack_end) { 
-		while (stack < estack_end) { 
-			addr = *stack++; 
-			if (__kernel_text_address(addr)) {
-				i += printk_address(addr);
-				i += printk(" "); 
-				if (i > 50) {
-					printk("\n"); 
-					i = 0;
-				}
-			}
+
+#define HANDLE_STACK(cond) \
+	do while (cond) { \
+		addr = *stack++; \
+		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 \
+			 * memory, it *may* be the address of a calling \
+			 * routine; if so, print it so that someone tracing \
+			 * down the cause of the crash will be able to figure \
+			 * out the call path that was taken. \
+			 */ \
+			i += printk_address(addr); \
+			if (i > 50) { \
+				printk("\n       "); \
+				i = 0; \
+			} \
+			else \
+				i += printk(" "); \
+		} \
+	} while (0)
+
+	for(i = 0; ; ) {
+		const char *id;
+		unsigned long *estack_end;
+		estack_end = in_exception_stack(cpu, (unsigned long)stack,
+						&used, &id);
+
+		if (estack_end) {
+			i += printk(" <%s> ", id);
+			HANDLE_STACK (stack < estack_end);
+			i += printk(" <EOE> ");
+			stack = (unsigned long *) estack_end[-2];
+			continue;
 		}
-		i += printk(" <EOE> "); 
-		i += 7;
-		stack = (unsigned long *) estack_end[-2]; 
-	}  
-
-	irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr);
-	irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE + 64);
-
-	if (stack >= irqstack && stack < irqstack_end) {
-		printk("<IRQ> ");  
-		while (stack < irqstack_end) {
-			addr = *stack++;
-			/*
-			 * If the address is either in the text segment of the
-			 * kernel, or in the region which contains vmalloc'ed
-			 * memory, it *may* be the address of a calling
-			 * routine; if so, print it so that someone tracing
-			 * down the cause of the crash will be able to figure
-			 * out the call path that was taken.
-			 */
-			 if (__kernel_text_address(addr)) {
-				 i += printk_address(addr);
-				 i += printk(" "); 
-				 if (i > 50) { 
-					printk("\n       ");
-					 i = 0;
-				 } 
+		if (irqstack_end) {
+			unsigned long *irqstack;
+			irqstack = irqstack_end -
+				(IRQSTACKSIZE - 64) / sizeof(*irqstack);
+
+			if (stack >= irqstack && stack < irqstack_end) {
+				i += printk(" <IRQ> ");
+				HANDLE_STACK (stack < irqstack_end);
+				stack = (unsigned long *) (irqstack_end[-1]);
+				irqstack_end = NULL;
+				i += printk(" <EOI> ");
+				continue;
 			}
-		} 
-		stack = (unsigned long *) (irqstack_end[-1]);
-		printk(" <EOI> ");
-		i += 7;
-	} 
-
-	while (((long) stack & (THREAD_SIZE-1)) != 0) {
-		addr = *stack++;
-		if (__kernel_text_address(addr)) {
-			i += printk_address(addr);
-			i += printk(" "); 
-			if (i > 50) { 
-				printk("\n       ");
-					 i = 0;
-			} 
 		}
+		break;
 	}
+
+	HANDLE_STACK (((long) stack & (THREAD_SIZE-1)) != 0);
+#undef HANDLE_STACK
 	printk("\n");
 }