Author: Andi Kleen <andi@xxxxxxxxxxxxxx>
AuthorDate: Thu, 12 Feb 2009 13:49:32 +0100
Commit: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Tue, 24 Feb 2009 13:24:42 -0800
x86, mce, cmci: avoid potential reentry of threshold interrupt
Impact: minor bugfix
The threshold handler on AMD (and soon on Intel) could be theoretically
reentered by the hardware. This could lead to corrupted events
because the machine check poll code assumes it is not reentered.
Move the APIC ACK to the end of the interrupt handler to let
the hardware avoid that.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/kernel/cpu/mcheck/threshold.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/threshold.c b/arch/x86/kernel/cpu/mcheck/threshold.c
index 4319142..e4b8a38 100644
--- a/arch/x86/kernel/cpu/mcheck/threshold.c
+++ b/arch/x86/kernel/cpu/mcheck/threshold.c
@@ -15,10 +15,11 @@ void (*mce_threshold_vector)(void) = default_threshold_interrupt;
asmlinkage void mce_threshold_interrupt(void)
{
- ack_APIC_irq();
exit_idle();
irq_enter();
inc_irq_stat(irq_threshold_count);
mce_threshold_vector();
irq_exit();
+ /* Ack only at the end to avoid potential reentry */
+ ack_APIC_irq();
}
--
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