patches.baytrail/0764-drm-i915-Don-t-destroy-the-vma-placeholder-during-ex.patch

From a35424bc1cd91732fb3dae696f5a65fab604ca5e Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 20 Aug 2013 12:56:40 +0100
Subject: drm/i915: Don't destroy the vma placeholder during execbuffer
 reservation

The execbuffer handle and exec_link were moved from the object into the
vma. As the vma may be unbound and destroyed whilst attempting to
reserve the execbuffer objects (either through a forced unbind to fix up
a misalignment or through an evict-everything call) we need to prevent
the free of the i915_vma itself. Otherwise not only is the list of
objects to reserve corrupt, but we continue to reference stale vma
entries.

Fixes kernel crash with i-g-t/gem_evict_everything

This regression has been introduced in

commit 04038a515d6eda6dd0857c0ade0b3950d372f4c0
Author:     Ben Widawsky <ben@bwidawsk.net>
AuthorDate: Wed Aug 14 11:38:36 2013 +0200

    drm/i915: Convert execbuf code to use vmas

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
References: http://www.spinics.net/lists/intel-gfx/msg32038.html
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68298
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit aaa0566792dc7ae68deb1959663581ea8c75d311)
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6820d0a1231f..29b7e1c32b84 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4159,6 +4159,11 @@ void i915_gem_vma_destroy(struct i915_vma *vma)
 {
 	WARN_ON(vma->node.allocated);
 	list_del(&vma->vma_link);
+
+	/* Keep the vma as a placeholder in the execbuffer reservation lists */
+	if (!list_empty(&vma->exec_list))
+		return;
+
 	kfree(vma);
 }
 
-- 
1.8.5.rc3