[PATCH 5.15 033/135] drm/msm: Ensure mmap offset is initialized

Greg Kroah-Hartman
2022-06-27T11:38:31Z

From: Rob Clark <robdclark@chromium.org>

[ Upstream commit 036d20726c30267724416e966c9f92db07de8081 ]

If a GEM object is allocated, and then exported as a dma-buf fd which is
mmap'd before or without the GEM buffer being directly mmap'd, the
vma_node could be unitialized. This leads to a situation where the CPU
mapping is not correctly torn down in drm_vma_node_unmap().

Fixes: e5516553999f ("drm: call drm_gem_object_funcs.mmap with fake offset")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220531200857.136547-1-robdclark@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/msm_drv.c | 2 +-
drivers/gpu/drm/msm/msm_drv.h | 1 +
drivers/gpu/drm/msm/msm_gem_prime.c | 15 +++++++++++++++
3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 9712582886aa..916361c30d77 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -1102,7 +1102,7 @@ static const struct drm_driver msm_driver = {
.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
.gem_prime_import_sg_table = msm_gem_prime_import_sg_table,
- .gem_prime_mmap = drm_gem_prime_mmap,
+ .gem_prime_mmap = msm_gem_prime_mmap,
#ifdef CONFIG_DEBUG_FS
.debugfs_init = msm_debugfs_init,
#endif
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index c552f0c3890c..bd5132bb9bde 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -298,6 +298,7 @@ unsigned long msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_t
void msm_gem_shrinker_init(struct drm_device *dev);
void msm_gem_shrinker_cleanup(struct drm_device *dev);

+int msm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
struct sg_table *msm_gem_prime_get_sg_table(struct drm_gem_object *obj);
int msm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
void msm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
diff --git a/drivers/gpu/drm/msm/msm_gem_prime.c b/drivers/gpu/drm/msm/msm_gem_prime.c
index 8a2d94bd5df2..02c70a0b2a03 100644
--- a/drivers/gpu/drm/msm/msm_gem_prime.c
+++ b/drivers/gpu/drm/msm/msm_gem_prime.c
@@ -11,6 +11,21 @@
#include "msm_drv.h"
#include "msm_gem.h"

+int msm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
+{
+ int ret;
+
+ /* Ensure the mmap offset is initialized. We lazily initialize it,
+ * so if it has not been first mmap'd directly as a GEM object, the
+ * mmap offset will not be already initialized.
+ */
+ ret = drm_gem_create_mmap_offset(obj);
+ if (ret)
+ return ret;
+
+ return drm_gem_prime_mmap(obj, vma);
+}
+
struct sg_table *msm_gem_prime_get_sg_table(struct drm_gem_object *obj)
{
struct msm_gem_object *msm_obj = to_msm_bo(obj);
--
2.35.1