[PATCH 2/9] drm/nouveau/debugfs: Move a variable assignment behind a null pointer check in nouveau_debugfs_pstate_get()

[Markus Elfring]

Date: Sat, 15 Apr 2023 21:24:43 +0200

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the function “nouveau_debugfs_pstate_get”.

Thus avoid the risk for undefined behaviour by moving the assignment
for the variable “ctrl” behind the null pointer check.

This issue was detected by using the Coccinelle software.

Fixes: 6e9fc177399f08446293fec7607913fdbc95e191 ("drm/nouveau/debugfs: add copy 
of sysfs pstate interface ported to debugfs")
Signed-off-by: Markus Elfring <elfr...@users.sourceforge.net>
---
 drivers/gpu/drm/nouveau/nouveau_debugfs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.c 
b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
index 44e26b6e74c7..a859a086f308 100644
--- a/drivers/gpu/drm/nouveau/nouveau_debugfs.c
+++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
@@ -73,13 +73,14 @@ nouveau_debugfs_pstate_get(struct seq_file *m, void *data)
 {
        struct drm_device *drm = m->private;
        struct nouveau_debugfs *debugfs = nouveau_debugfs(drm);
-       struct nvif_object *ctrl = &debugfs->ctrl;
+       struct nvif_object *ctrl;
        struct nvif_control_pstate_info_v0 info = {};
        int ret, i;

        if (!debugfs)
                return -ENODEV;

+       ctrl = &debugfs->ctrl;
        ret = nvif_mthd(ctrl, NVIF_CONTROL_PSTATE_INFO, &info, sizeof(info));
        if (ret)
                return ret;
--
2.40.0