[PATCH v2] 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().

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().

Free 'group' when alloc_workqueue() failed in hw_engine_group_alloc(), and
remove wrong kfree() in xe_hw_engine_setup_groups() to fix this problem.
It's safe to remove these kfree() because drmm_add_action_or_reset()
can free these by calling hw_engine_group_free().

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 <su...@nfschina.com>
---
v2:
 - remove wrong destroy_workqueue() and kfree() in v1 patch
v1:
 - https://lore.kernel.org/all/20241114063942.3448607-1-su...@nfschina.com/

 drivers/gpu/drm/xe/xe_hw_engine_group.c | 32 +++++++------------------
 1 file changed, 9 insertions(+), 23 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..3bfa002734ad 100644
--- a/drivers/gpu/drm/xe/xe_hw_engine_group.c
+++ b/drivers/gpu/drm/xe/xe_hw_engine_group.c
@@ -58,8 +58,10 @@ hw_engine_group_alloc(struct xe_device *xe)
                return ERR_PTR(-ENOMEM);
 
        group->resume_wq = alloc_workqueue("xe-resume-lr-jobs-wq", 0, 0);
-       if (!group->resume_wq)
+       if (!group->resume_wq) {
+               kfree(group);
                return ERR_PTR(-ENOMEM);
+       }
 
        init_rwsem(&group->mode_sem);
        INIT_WORK(&group->resume_work, hw_engine_group_resume_lr_jobs_func);
@@ -84,25 +86,18 @@ int xe_hw_engine_setup_groups(struct xe_gt *gt)
        enum xe_hw_engine_id id;
        struct xe_hw_engine_group *group_rcs_ccs, *group_bcs, *group_vcs_vecs;
        struct xe_device *xe = gt_to_xe(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;
-       }
+       if (IS_ERR(group_bcs))
+               return PTR_ERR(group_bcs);
 
        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;
-       }
+       if (IS_ERR(group_vcs_vecs))
+               return PTR_ERR(group_vcs_vecs);
 
        for_each_hw_engine(hwe, gt, id) {
                switch (hwe->class) {
@@ -125,15 +120,6 @@ int xe_hw_engine_setup_groups(struct xe_gt *gt)
        }
 
        return 0;
-
-err_group_vcs_vecs:
-       kfree(group_vcs_vecs);
-err_group_bcs:
-       kfree(group_bcs);
-err_group_rcs_ccs:
-       kfree(group_rcs_ccs);
-
-       return err;
 }
 
 /**
-- 
2.30.2