From 00f8a489477d0924f6967f7d1209558dc8e48381 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= <thomas.hellstrom@linux.intel.com>
Date: Tue, 31 Aug 2021 09:15:36 +0200
Subject: drm/ttm: Fix ttm_bo_move_memcpy() for subclassed struct ttm_resource
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Git-commit: efcefc7127290e7e9fa98dea029163ad8eda8fb3
Patch-mainline: v5.15-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

The code was making a copy of a struct ttm_resource. However,
recently the struct ttm_resources were allowed to be subclassed and
also were allowed to be malloced, hence the driver could end up assuming
the copy we handed it was subclassed and worse, the original could have
been freed at this point.

Fix this by using the original struct ttm_resource before it is
potentially freed in ttm_bo_move_sync_cleanup()

v2: Base on drm-misc-next-fixes rather than drm-tip.

Reported-by: Ben Skeggs <skeggsb@gmail.com>
Reported-by: Dave Airlie <airlied@gmail.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: <stable@vger.kernel.org>
Fixes: 3bf3710e3718 ("drm/ttm: Add a generic TTM memcpy move for page-based iomem")
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210831071536.80636-1-thomas.hellstrom@linux.intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/ttm/ttm_bo_util.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 763fa6f4e07d..1c5ffe2935af 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -143,7 +143,6 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
 	struct ttm_resource *src_mem = bo->resource;
 	struct ttm_resource_manager *src_man =
 		ttm_manager_type(bdev, src_mem->mem_type);
-	struct ttm_resource src_copy = *src_mem;
 	union {
 		struct ttm_kmap_iter_tt tt;
 		struct ttm_kmap_iter_linear_io io;
@@ -173,11 +172,11 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
 	}
 
 	ttm_move_memcpy(bo, dst_mem->num_pages, dst_iter, src_iter);
-	src_copy = *src_mem;
-	ttm_bo_move_sync_cleanup(bo, dst_mem);
 
 	if (!src_iter->ops->maps_tt)
-		ttm_kmap_iter_linear_io_fini(&_src_iter.io, bdev, &src_copy);
+		ttm_kmap_iter_linear_io_fini(&_src_iter.io, bdev, src_mem);
+	ttm_bo_move_sync_cleanup(bo, dst_mem);
+
 out_src_iter:
 	if (!dst_iter->ops->maps_tt)
 		ttm_kmap_iter_linear_io_fini(&_dst_iter.io, bdev, dst_mem);
-- 
2.38.1