2 files changed, 16 insertions, 4 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 7305f7dfc7ab..f84cfd1b0c0b 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -110,11 +110,16 @@ void __show_regs(struct pt_regs *regs, int all)
         get_debugreg(d1, 1);
         get_debugreg(d2, 2);
         get_debugreg(d3, 3);
-        printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
-                        d0, d1, d2, d3);
-
         get_debugreg(d6, 6);
         get_debugreg(d7, 7);
+
+        /* Only print out debug registers if they are in their non-default state. */
+        if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
+            (d6 == DR6_RESERVED) && (d7 == 0x400))
+                return;
+
+        printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
+                        d0, d1, d2, d3);
         printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n",
                         d6, d7);
 }
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 355ae06dbf94..a8b9abc5459a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -105,11 +105,18 @@ void __show_regs(struct pt_regs *regs, int all)
         get_debugreg(d0, 0);
         get_debugreg(d1, 1);
         get_debugreg(d2, 2);
-        printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
         get_debugreg(d3, 3);
         get_debugreg(d6, 6);
         get_debugreg(d7, 7);
+
+        /* Only print out debug registers if they are in their non-default state. */
+        if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
+            (d6 == DR6_RESERVED) && (d7 == 0x400))
+                return;
+
+        printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
         printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
+
 }
 
 void release_thread(struct task_struct *dead_task)