From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Tue, 9 Jan 2018 19:18:59 +0100
Subject: drm/amdgpu: fix amdgpu_vm_pasid_fault_credit
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Git-commit: d958939afc39391c0d007a0ca43153856d63ec2a
Patch-mainline: v4.16-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

As soon as the lock is dropped the VM pointer can be invalid.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2477,17 +2477,21 @@ bool amdgpu_vm_pasid_fault_credit(struct
 
 	spin_lock(&adev->vm_manager.pasid_lock);
 	vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
-	spin_unlock(&adev->vm_manager.pasid_lock);
-	if (!vm)
+	if (!vm) {
 		/* VM not found, can't track fault credit */
+		spin_unlock(&adev->vm_manager.pasid_lock);
 		return true;
+	}
 
 	/* No lock needed. only accessed by IRQ handler */
-	if (!vm->fault_credit)
+	if (!vm->fault_credit) {
 		/* Too many faults in this VM */
+		spin_unlock(&adev->vm_manager.pasid_lock);
 		return false;
+	}
 
 	vm->fault_credit--;
+	spin_unlock(&adev->vm_manager.pasid_lock);
 	return true;
 }