[PATCH] i386: Fix race in IO-APIC routing entry setup.
Interrupt could happen between setting the IO-APIC entry
and setting its interrupt data.
Pointed out by Linus.
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index 3b7a63e..e33b7a8 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -153,14 +153,20 @@
* the interrupt, and we need to make sure the entry is fully populated
* before that happens.
*/
+static void
+__ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
+{
+ union entry_union eu;
+ eu.entry = e;
+ io_apic_write(apic, 0x11 + 2*pin, eu.w2);
+ io_apic_write(apic, 0x10 + 2*pin, eu.w1);
+}
+
static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
{
unsigned long flags;
- union entry_union eu;
- eu.entry = e;
spin_lock_irqsave(&ioapic_lock, flags);
- io_apic_write(apic, 0x11 + 2*pin, eu.w2);
- io_apic_write(apic, 0x10 + 2*pin, eu.w1);
+ __ioapic_write_entry(apic, pin, e);
spin_unlock_irqrestore(&ioapic_lock, flags);
}
@@ -1360,8 +1366,8 @@
if (!apic && (irq < 16))
disable_8259A_irq(irq);
}
- ioapic_write_entry(apic, pin, entry);
spin_lock_irqsave(&ioapic_lock, flags);
+ __ioapic_write_entry(apic, pin, entry);
set_native_irq_info(irq, TARGET_CPUS);
spin_unlock_irqrestore(&ioapic_lock, flags);
}
@@ -2856,8 +2862,8 @@
if (!ioapic && (irq < 16))
disable_8259A_irq(irq);
- ioapic_write_entry(ioapic, pin, entry);
spin_lock_irqsave(&ioapic_lock, flags);
+ __ioapic_write_entry(ioapic, pin, entry);
set_native_irq_info(irq, TARGET_CPUS);
spin_unlock_irqrestore(&ioapic_lock, flags);