From 6aa8dd31fc0032e226b8a9cbe17f4e4a12fec9b9 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Wed, 17 Jun 2009 10:53:47 -0300 Subject: KVM: protect concurrent make_all_cpus_request commit 84261923d3dddb766736023bead6fa07b7e218d5 upstream. make_all_cpus_request contains a race condition which can trigger false request completed status, as follows: CPU0 CPU1 if (test_and_set_bit(req,&vcpu->requests)) .... if (test_and_set_bit(req,&vcpu->requests)) .. return proceed to smp_call_function_many(wait=1) Use a spinlock to serialize concurrent CPUs. Signed-off-by: Andrea Arcangeli Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity Signed-off-by: Greg Kroah-Hartman --- include/linux/kvm_host.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 894a56e365e..5eed8fa02c0 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -125,6 +125,7 @@ struct kvm_kernel_irq_routing_entry { struct kvm { struct mutex lock; /* protects the vcpus array and APIC accesses */ spinlock_t mmu_lock; + spinlock_t requests_lock; struct rw_semaphore slots_lock; struct mm_struct *mm; /* userspace tied to this vm */ int nmemslots; -- cgit v1.2.3-18-g5258