From 1bf1b431d98d7e5b5419876d4c219469e60693e1 Mon Sep 17 00:00:00 2001 From: Oded Gabbay Date: Thu, 16 Apr 2015 17:08:44 +0300 Subject: [PATCH] iommu/amd: Fix bug in put_pasid_state_wait 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 Cc: stable@vger.kernel.org #v4.0 Signed-off-by: Joerg Roedel --- 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 a1cbba9056fd..3465faf1809e 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); }