[3.19.y-ckt stable] Patch "drm/radeon: fix lockup when BOs aren't part of the VM on release" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    drm/radeon: fix lockup when BOs aren't part of the VM on release

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From 4e5bbbb190b7440f0b2f9bb09a362c344e01ae62 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig at amd.com>
Date: Mon, 27 Apr 2015 17:04:34 +0200
Subject: drm/radeon: fix lockup when BOs aren't part of the VM on release
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Content-Type: text/plain; charset=UTF-8
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commit 26d4d129b6042197b4cbc8341c0618f99231af2f upstream.

If we unmap BOs before releasing them them the intervall tree locks
up because we try to remove an entry not inside the tree.

Based on a patch from Michel Dänzer.

Signed-off-by: Christian König <christian.koenig at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/gpu/drm/radeon/radeon_vm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_vm.c b/drivers/gpu/drm/radeon/radeon_vm.c
index 2a5a4a9..16d8e95 100644
--- a/drivers/gpu/drm/radeon/radeon_vm.c
+++ b/drivers/gpu/drm/radeon/radeon_vm.c
@@ -1107,7 +1107,8 @@ void radeon_vm_bo_rmv(struct radeon_device *rdev,
 	list_del(&bo_va->bo_list);

 	mutex_lock(&vm->mutex);
-	interval_tree_remove(&bo_va->it, &vm->va);
+	if (bo_va->it.start || bo_va->it.last)
+		interval_tree_remove(&bo_va->it, &vm->va);
 	spin_lock(&vm->status_lock);
 	list_del(&bo_va->vm_status);

--
1.9.1