> From: Paolo Bonzini
> Sent: Tuesday, April 21, 2015 10:48 AM
Hi, big thanks to all involved in this and to Brad for endless reboots ;-)
>> Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
>> Fixes: 33e4c68656a2e461b296ce714ec322978de85412
>> Cc: stable@xxxxxxxxxxxxxxx # 2.6.32+
>> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> ---
>> The race was reported in 3.17+ by Brad Campbell and in
>> 2.6.32 by Saso Slavicic, so it qualifies for stable.
> Patch for kernels before 3.17:
This will probably end up in RHEL6 sooner or later (but probably not before
6.7)?
As I like to experiment a bit, would this patch do for -2.6.32-504.12.2.el6
kernel? The code in that function is somewhat different...
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -230,8 +230,13 @@
static inline int apic_test_and_set_irr(int vec, struct kvm_lapic *apic)
{
+ int ret = apic_test_and_set_vector(vec, apic->regs + APIC_IRR);
+ /*
+ * irr_pending must be true if any interrupt is pending; set it
after
+ * APIC_IRR to avoid race with apic_clear_irr
+ */
apic->irr_pending = true;
- return apic_test_and_set_vector(vec, apic->regs + APIC_IRR);
+ return ret;
}
static inline int apic_search_irr(struct kvm_lapic *apic)
Regards,
Saso Slavicic
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