[PATCH 1/9] drm/nouveau/debugfs: Move an expression into a function call parameter in nouveau_debugfs_pstate_set()

[Markus Elfring]

Date: Sat, 15 Apr 2023 21:06:06 +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_set”.

Thus avoid the risk for undefined behaviour by moving the usage
of an expression into a parameter for a function call at the end.

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 <elfring at users.sourceforge.net>
---
 drivers/gpu/drm/nouveau/nouveau_debugfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.c b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
index 2a36d1ca8fda..44e26b6e74c7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_debugfs.c
+++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
@@ -144,7 +144,6 @@ nouveau_debugfs_pstate_set(struct file *file, const char __user *ubuf,
 	struct seq_file *m = file->private_data;
 	struct drm_device *drm = m->private;
 	struct nouveau_debugfs *debugfs = nouveau_debugfs(drm);
-	struct nvif_object *ctrl = &debugfs->ctrl;
 	struct nvif_control_pstate_user_v0 args = { .pwrsrc = -EINVAL };
 	char buf[32] = {}, *tmp, *cur = buf;
 	long value, ret;
@@ -188,7 +187,8 @@ nouveau_debugfs_pstate_set(struct file *file, const char __user *ubuf,
 		return ret;
 	}

-	ret = nvif_mthd(ctrl, NVIF_CONTROL_PSTATE_USER, &args, sizeof(args));
+	ret = nvif_mthd(&debugfs->ctrl, NVIF_CONTROL_PSTATE_USER,
+			&args, sizeof(args));
 	pm_runtime_put_autosuspend(drm->dev);
 	if (ret < 0)
 		return ret;
--
2.40.0