From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Wed, 24 Jan 2018 13:37:48 +0100
Subject: drm/amdgpu: fix locking in vega10_ih_prescreen_iv
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Git-commit: 153b9e1b75441cd51f69e88b4748c23166de0d64
Patch-mainline: v4.16-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

The vm pointer can become invalid as soon as the lock is released.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/vega10_ih.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
@@ -278,9 +278,9 @@ static bool vega10_ih_prescreen_iv(struc
 	/* Track retry faults in per-VM fault FIFO. */
 	spin_lock(&adev->vm_manager.pasid_lock);
 	vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
-	spin_unlock(&adev->vm_manager.pasid_lock);
 	if (WARN_ON_ONCE(!vm)) {
 		/* VM not found, process it normally */
+		spin_unlock(&adev->vm_manager.pasid_lock);
 		amdgpu_ih_clear_fault(adev, key);
 		return true;
 	}
@@ -288,9 +288,11 @@ static bool vega10_ih_prescreen_iv(struc
 	r = kfifo_put(&vm->faults, key);
 	if (!r) {
 		/* FIFO is full. Ignore it until there is space */
+		spin_unlock(&adev->vm_manager.pasid_lock);
 		amdgpu_ih_clear_fault(adev, key);
 		goto ignore_iv;
 	}
+	spin_unlock(&adev->vm_manager.pasid_lock);
 
 	/* It's the first fault for this address, process it normally */
 	return true;