1 files changed, 21 insertions, 6 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index a8e3eb83466c..482ec3af2067 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -306,19 +306,20 @@ dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
                         == NOTIFY_STOP)
                 return;
 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
-#ifdef CONFIG_KPROBES
+
         if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
                         == NOTIFY_STOP)
                 return;
-#else
-        if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
-                        == NOTIFY_STOP)
-                return;
-#endif
 
+        /*
+         * Let others (NMI) know that the debug stack is in use
+         * as we may switch to the interrupt stack.
+         */
+        debug_stack_usage_inc();
         preempt_conditional_sti(regs);
         do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
         preempt_conditional_cli(regs);
+        debug_stack_usage_dec();
 }
 
 #ifdef CONFIG_X86_64
@@ -411,6 +412,12 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
                                                         SIGTRAP) == NOTIFY_STOP)
                 return;
 
+        /*
+         * Let others (NMI) know that the debug stack is in use
+         * as we may switch to the interrupt stack.
+         */
+        debug_stack_usage_inc();
+
         /* It's safe to allow irq's after DR6 has been saved */
         preempt_conditional_sti(regs);
 
@@ -418,6 +425,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
                 handle_vm86_trap((struct kernel_vm86_regs *) regs,
                                 error_code, 1);
                 preempt_conditional_cli(regs);
+                debug_stack_usage_dec();
                 return;
         }
 
@@ -437,6 +445,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
         if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
                 send_sigtrap(tsk, regs, error_code, si_code);
         preempt_conditional_cli(regs);
+        debug_stack_usage_dec();
 
         return;
 }
@@ -723,4 +732,10 @@ void __init trap_init(void)
         cpu_init();
 
         x86_init.irqs.trap_init();
+
+#ifdef CONFIG_X86_64
+        memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16);
+        set_nmi_gate(1, &debug);
+        set_nmi_gate(3, &int3);
+#endif
 }