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authorMichael S. Tsirkin <mst@redhat.com>2010-09-19 19:02:31 +0200
committerMarcelo Tosatti <mtosatti@redhat.com>2010-09-23 11:31:51 -0300
commit6bbfb2653177a00f70e57e53625502d43804fed0 (patch)
treeb0196884ead501481a3ae3a27d45b41b43ec117d /virt
parentc79bd89282136a4516e842fa542d6abf902ddeac (diff)
downloadlinux-2.6.38-lt-ux500-6bbfb2653177a00f70e57e53625502d43804fed0.tar.gz
KVM: fix irqfd assign/deassign race
I think I see the following (theoretical) race: During irqfd assign, we drop irqfds lock before we schedule inject work. Therefore, deassign running on another CPU could cause shutdown and flush to run before inject, causing user after free in inject. A simple fix it to schedule inject under the lock. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/eventfd.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 66cf65b510b..c1f1e3c6298 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -218,7 +218,6 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
events = file->f_op->poll(file, &irqfd->pt);
list_add_tail(&irqfd->list, &kvm->irqfds.items);
- spin_unlock_irq(&kvm->irqfds.lock);
/*
* Check if there was an event already pending on the eventfd
@@ -227,6 +226,8 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
if (events & POLLIN)
schedule_work(&irqfd->inject);
+ spin_unlock_irq(&kvm->irqfds.lock);
+
/*
* do not drop the file until the irqfd is fully initialized, otherwise
* we might race against the POLLHUP