From 7cf4448fa627fe6d08d994967d7adec39ee89bde Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 28 Jan 2020 18:34:58 +0000
Subject: drm/i915/selftests: Lock the drm_mm as we search
Git-commit: 6717f7c32b33c2b13627dce309400abe7ac68392
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Hold onto the vm->mutex (to lock the drm_mm) to ensure that the rbtree
is stable as we search it for our scratch node.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128183458.3860022-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index 130c4c522686..375d864736f3 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -1465,9 +1465,12 @@ static int igt_ctx_readonly(void *arg)
 
 static int check_scratch(struct i915_address_space *vm, u64 offset)
 {
-	struct drm_mm_node *node =
-		__drm_mm_interval_first(&vm->mm,
-					offset, offset + sizeof(u32) - 1);
+	struct drm_mm_node *node;
+
+	mutex_lock(&vm->mutex);
+	node = __drm_mm_interval_first(&vm->mm,
+				       offset, offset + sizeof(u32) - 1);
+	mutex_unlock(&vm->mutex);
 	if (!node || node->start > offset)
 		return 0;
 
-- 
2.28.0