4 files changed, 21 insertions, 6 deletions

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index f8119b582c3c..1d2091a226bc 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -715,4 +715,6 @@ static inline void exiting_ack_irq(void)
         ack_APIC_irq();
 }
 
+extern void ioapic_zap_locks(void);
+
 #endif /* _ASM_X86_APIC_H */
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 2627a81253ee..81aa73b8ecf5 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -199,7 +199,7 @@ static void acpi_register_lapic(int id, u8 enabled)
 {
         unsigned int ver = 0;
 
-        if (id >= (MAX_LOCAL_APIC-1)) {
+        if (id >= MAX_LOCAL_APIC) {
                 printk(KERN_INFO PREFIX "skipped apicid that is too big\n");
                 return;
         }
@@ -1120,6 +1120,7 @@ int mp_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
         int ioapic;
         int ioapic_pin;
         struct io_apic_irq_attr irq_attr;
+        int ret;
 
         if (acpi_irq_model != ACPI_IRQ_MODEL_IOAPIC)
                 return gsi;
@@ -1149,7 +1150,9 @@ int mp_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
         set_io_apic_irq_attr(&irq_attr, ioapic, ioapic_pin,
                              trigger == ACPI_EDGE_SENSITIVE ? 0 : 1,
                              polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
-        io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr);
+        ret = io_apic_set_pci_routing(dev, gsi_to_irq(gsi), &irq_attr);
+        if (ret < 0)
+                gsi = INT_MIN;
 
         return gsi;
 }
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9ed796ccc32c..e63a5bd2a78f 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1534,6 +1534,11 @@ void intel_ir_io_apic_print_entries(unsigned int apic,
         }
 }
 
+void ioapic_zap_locks(void)
+{
+        raw_spin_lock_init(&ioapic_lock);
+}
+
 __apicdebuginit(void) print_IO_APIC(int ioapic_idx)
 {
         union IO_APIC_reg_00 reg_00;
@@ -3375,12 +3380,15 @@ int io_apic_setup_irq_pin_once(unsigned int irq, int node,
 {
         unsigned int ioapic_idx = attr->ioapic, pin = attr->ioapic_pin;
         int ret;
+        struct IO_APIC_route_entry orig_entry;
 
         /* Avoid redundant programming */
         if (test_bit(pin, ioapics[ioapic_idx].pin_programmed)) {
-                pr_debug("Pin %d-%d already programmed\n",
-                         mpc_ioapic_id(ioapic_idx), pin);
-                return 0;
+                pr_debug("Pin %d-%d already programmed\n", mpc_ioapic_id(ioapic_idx), pin);
+                orig_entry = ioapic_read_entry(attr->ioapic, pin);
+                if (attr->trigger == orig_entry.trigger && attr->polarity == orig_entry.polarity)
+                        return 0;
+                return -EBUSY;
         }
         ret = io_apic_setup_irq_pin(irq, node, attr);
         if (!ret)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 74467feb4dc5..e0e0841eef45 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -128,7 +128,9 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
         cpu_emergency_svm_disable();
 
         lapic_shutdown();
-#if defined(CONFIG_X86_IO_APIC)
+#ifdef CONFIG_X86_IO_APIC
+        /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
+        ioapic_zap_locks();
         disable_IO_APIC();
 #endif
 #ifdef CONFIG_HPET_TIMER