Hi,
On 10/12/21 15:25, Colin King wrote:
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
The assignment of pointer backup_bo dereferences pointer backup before
backup is null checked, this could lead to a null pointer dereference
issue. Fix this by only assigning backup_bo after backup has been null
checked.
Addresses-Coverity: ("Dereference before null check")
Fixes: c56ce9565374 ("drm/i915 Implement LMEM backup and restore for suspend / resume")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
There's not really a pointer dereference here, just pointer arithmetics,
so the code should be safe (but admittedly fragile), so to keep Coverity
happy,
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
index 3b6d14b5c604..4ec6c557083a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
@@ -149,7 +149,7 @@ static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
struct i915_gem_ttm_pm_apply *pm_apply =
container_of(apply, typeof(*pm_apply), base);
struct drm_i915_gem_object *backup = obj->ttm.backup;
- struct ttm_buffer_object *backup_bo = i915_gem_to_ttm(backup);
+ struct ttm_buffer_object *backup_bo;
struct ttm_operation_ctx ctx = {};
int err;
@@ -163,6 +163,8 @@ static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
if (err)
return err;
+ backup_bo = i915_gem_to_ttm(backup);
+
/* Content may have been swapped. */
err = ttm_tt_populate(backup_bo->bdev, backup_bo->ttm, &ctx);
if (!err) {
