x86/kernel: Fix output of show_stack_log_lvl()

show_stack_log_lvl() does not set the log level after a new line, the
following messages printed with pr_cont() are thus assigned to the
default log level.

This patch prepends the log level to the next message following a new
line.

print_trace_address() uses printk(log_lvl). Using printk() with just
a log level is ignored and thus has no effect on the next pr_cont().
We need to prepend the log level directly into the message.

Signed-off-by: Adrien Schildknecht <adrien+dev@schischi.me>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1424399661-20327-1-git-send-email-adrien+dev@schischi.me
Signed-off-by: Borislav Petkov <bp@suse.de>

arch/x86/kernel/dumpstack.c

@@ -25,10 +25,12 @@ unsigned int code_bytes = 64;
 int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
 static int die_counter;
 
-static void printk_stack_address(unsigned long address, int reliable)
+static void printk_stack_address(unsigned long address, int reliable,
+		void *data)
 {
-	pr_cont(" [<%p>] %s%pB\n",
-		(void *)address, reliable ? "" : "? ", (void *)address);
+	printk("%s [<%p>] %s%pB\n",
+		(char *)data, (void *)address, reliable ? "" : "? ",
+		(void *)address);
 }
 
 void printk_address(unsigned long address)
@@ -155,8 +157,7 @@ static int print_trace_stack(void *data, char *name)
 static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
 	touch_nmi_watchdog();
-	printk(data);
-	printk_stack_address(addr, reliable);
+	printk_stack_address(addr, reliable, data);
 }
 
 static const struct stacktrace_ops print_trace_ops = {

arch/x86/kernel/dumpstack_32.c

@@ -108,9 +108,12 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (kstack_end(stack))
 			break;
-		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			pr_cont("\n");
-		pr_cont(" %08lx", *stack++);
+		if ((i % STACKSLOTS_PER_LINE) == 0) {
+			if (i != 0)
+				pr_cont("\n");
+			printk("%s %08lx", log_lvl, *stack++);
+		} else
+			pr_cont(" %08lx", *stack++);
 		touch_nmi_watchdog();
 	}
 	pr_cont("\n");

arch/x86/kernel/dumpstack_64.c

@@ -283,9 +283,12 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 		if (((long) stack & (THREAD_SIZE-1)) == 0)
 			break;
 		}
-		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			pr_cont("\n");
-		pr_cont(" %016lx", *stack++);
+		if ((i % STACKSLOTS_PER_LINE) == 0) {
+			if (i != 0)
+				pr_cont("\n");
+			printk("%s %016lx", log_lvl, *stack++);
+		} else
+			pr_cont(" %016lx", *stack++);
 		touch_nmi_watchdog();
 	}
 	preempt_enable();