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Commit 516d2836 authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
Browse files

[PATCH] x86-64: 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: default avatarAndi Kleen <ak@suse.de>
parent d15512f4

arch/x86_64/kernel/io_apic.c

+9 −3
Original line number Diff line number Diff line
@@ -174,14 +174,20 @@ static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin) 
 * 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)

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);

}



static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)

{

	unsigned long flags;

	spin_lock_irqsave(&ioapic_lock, flags);

	__ioapic_write_entry(apic, pin, e);

	spin_unlock_irqrestore(&ioapic_lock, flags);

}