[PATCH] kvm: fix crash on irqfd deassign

From: Michael S. Tsirkin
Date: Thu Mar 17 2011 - 04:54:18 EST


irqfd in kvm used flush_work incorrectly:
it assumed that work scheduled previously can't run
after flush_work, but since kvm uses a non-reentrant
workqueue (by means of schedule_work)
we need flush_work_sync to get that guarantee.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Reported-by: Jean-Philippe Menil <jean-philippe.menil@xxxxxxxxxxxxxx>
Tested-by: Jean-Philippe Menil <jean-philippe.menil@xxxxxxxxxxxxxx>
---

Note: this is needed for kernel 2.6.39 and earlier.

virt/kvm/eventfd.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 2ca4535..cdf51c9 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -90,7 +90,7 @@ irqfd_shutdown(struct work_struct *work)
* We know no new events will be scheduled at this point, so block
* until all previously outstanding events have completed
*/
- flush_work(&irqfd->inject);
+ flush_work_sync(&irqfd->inject);

/*
* It is now safe to release the object's resources
--
1.7.3.2.91.g446ac
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