[PATCH] drm/xe/hw_engine_group: Fix bad free in xe_hw_engine_setup_groups()

[Su Hui]

Clang static checker(scan-build) warning：
drivers/gpu/drm/xe/xe_hw_engine_group.c: line 134, column 2
Argument to kfree() is a constant address (18446744073709551604), which
is not memory allocated by malloc().

There are some problems in hw_engine_group_alloc() and
xe_hw_engine_setup_groups(). First, kfree() can only handle NULL
pointers instead of negitave error codes. When hw_engine_group_alloc()
failed, there is a bad kfree call for negitave error codes in
xe_hw_engine_setup_groups(). Second, when drmm_add_action_or_reset()
failed, destroy_workqueue() should be called to free 'group->resume_wq'.

Free 'group' and destroy 'group->resume_wq' when hw_engine_group_alloc()
failed to fix these problems.

Fixes: d16ef1a18e39 ("drm/xe/exec: Switch hw engine group execution mode upon job submission")
Fixes: f784750c670f ("drm/xe/hw_engine_group: Introduce xe_hw_engine_group")
Signed-off-by: Su Hui <suhui at nfschina.com>
---
 drivers/gpu/drm/xe/xe_hw_engine_group.c | 31 ++++++++++++++-----------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_hw_engine_group.c b/drivers/gpu/drm/xe/xe_hw_engine_group.c
index 82750520a90a..ee2cb32817fa 100644
--- a/drivers/gpu/drm/xe/xe_hw_engine_group.c
+++ b/drivers/gpu/drm/xe/xe_hw_engine_group.c
@@ -51,7 +51,7 @@ static struct xe_hw_engine_group *
 hw_engine_group_alloc(struct xe_device *xe)
 {
 	struct xe_hw_engine_group *group;
-	int err;
+	int err = -ENOMEM;
 
 	group = kzalloc(sizeof(*group), GFP_KERNEL);
 	if (!group)
@@ -59,7 +59,7 @@ hw_engine_group_alloc(struct xe_device *xe)
 
 	group->resume_wq = alloc_workqueue("xe-resume-lr-jobs-wq", 0, 0);
 	if (!group->resume_wq)
-		return ERR_PTR(-ENOMEM);
+		goto free_group;
 
 	init_rwsem(&group->mode_sem);
 	INIT_WORK(&group->resume_work, hw_engine_group_resume_lr_jobs_func);
@@ -67,9 +67,15 @@ hw_engine_group_alloc(struct xe_device *xe)
 
 	err = drmm_add_action_or_reset(&xe->drm, hw_engine_group_free, group);
 	if (err)
-		return ERR_PTR(err);
+		goto destroy_wq;
 
 	return group;
+
+destroy_wq:
+	destroy_workqueue(group->resume_wq);
+free_group:
+	kfree(group);
+	return ERR_PTR(err);
 }
 
 /**
@@ -87,21 +93,19 @@ int xe_hw_engine_setup_groups(struct xe_gt *gt)
 	int err;
 
 	group_rcs_ccs = hw_engine_group_alloc(xe);
-	if (IS_ERR(group_rcs_ccs)) {
-		err = PTR_ERR(group_rcs_ccs);
-		goto err_group_rcs_ccs;
-	}
+	if (IS_ERR(group_rcs_ccs))
+		return PTR_ERR(group_rcs_ccs);
 
 	group_bcs = hw_engine_group_alloc(xe);
 	if (IS_ERR(group_bcs)) {
 		err = PTR_ERR(group_bcs);
-		goto err_group_bcs;
+		goto free_group_rcs_ccs;
 	}
 
 	group_vcs_vecs = hw_engine_group_alloc(xe);
 	if (IS_ERR(group_vcs_vecs)) {
 		err = PTR_ERR(group_vcs_vecs);
-		goto err_group_vcs_vecs;
+		goto free_group_bcs;
 	}
 
 	for_each_hw_engine(hwe, gt, id) {
@@ -126,13 +130,12 @@ int xe_hw_engine_setup_groups(struct xe_gt *gt)
 
 	return 0;
 
-err_group_vcs_vecs:
-	kfree(group_vcs_vecs);
-err_group_bcs:
+free_group_bcs:
+	destroy_workqueue(group_bcs->resume_wq);
 	kfree(group_bcs);
-err_group_rcs_ccs:
+free_group_rcs_ccs:
+	destroy_workqueue(group_rcs_ccs->resume_wq);
 	kfree(group_rcs_ccs);
-
 	return err;
 }
 
-- 
2.30.2