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Subject[PATCH] iommu/amd: Fix bug in put_pasid_state_wait
Date
This patch fixes a bug in put_pasid_state_wait that appeared in kernel 4.0
The bug is that pasid_state->count wasn't decremented before entering the
wait_event. Thus, the condition in wait_event will never be true.

The fix is to decrement (atomically) the pasid_state->count before the
wait_event.

Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
Cc: stable@vger.kernel.org
---
drivers/iommu/amd_iommu_v2.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 6d5a5c4..173e70d 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -266,6 +266,7 @@ static void put_pasid_state(struct pasid_state *pasid_state)

static void put_pasid_state_wait(struct pasid_state *pasid_state)
{
+ atomic_dec(&pasid_state->count);
wait_event(pasid_state->wq, !atomic_read(&pasid_state->count));
free_pasid_state(pasid_state);
}
--
1.9.1


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