[bug report] drm: add DRM_SET_CLIENT_NAME ioctl

[Dan Carpenter]

Hello Pierre-Eric Pelloux-Prayer,

Commit 56c594d8df64 ("drm: add DRM_SET_CLIENT_NAME ioctl") from Oct
3, 2024 (linux-next), leads to the following Smatch static checker
warning:

	drivers/gpu/drm/drm_debugfs.c:104 drm_clients_info()
	warn: was precision intended? '64'

drivers/gpu/drm/drm_debugfs.c
    73 static int drm_clients_info(struct seq_file *m, void *data)
    74 {
    75         struct drm_debugfs_entry *entry = m->private;
    76         struct drm_device *dev = entry->dev;
    77         struct drm_file *priv;
    78         kuid_t uid;
    79 
    80         seq_printf(m,
    81                    "%20s %5s %3s master a %5s %10s %*s\n",
                                                          ^^^
this was probably intended to be %.*s

    82                    "command",
    83                    "tgid",
    84                    "dev",
    85                    "uid",
    86                    "magic",
    87                    DRM_CLIENT_NAME_MAX_LEN,
    88                    "name");
    89 
    90         /* dev->filelist is sorted youngest first, but we want to present
    91          * oldest first (i.e. kernel, servers, clients), so walk backwardss.
    92          */
    93         mutex_lock(&dev->filelist_mutex);
    94         list_for_each_entry_reverse(priv, &dev->filelist, lhead) {
    95                 bool is_current_master = drm_is_current_master(priv);
    96                 struct task_struct *task;
    97                 struct pid *pid;
    98 
    99                 mutex_lock(&priv->client_name_lock);
    100                 rcu_read_lock(); /* Locks priv->pid and pid_task()->comm! */
    101                 pid = rcu_dereference(priv->pid);
    102                 task = pid_task(pid, PIDTYPE_TGID);
    103                 uid = task ? __task_cred(task)->euid : GLOBAL_ROOT_UID;
--> 104                 seq_printf(m, "%20s %5d %3d   %c    %c %5d %10u %*s\n",
                                                                         ^^
And this as well.  But why bother?  We know these strings are NUL terminated.

    105                            task ? task->comm : "<unknown>",
    106                            pid_vnr(pid),
    107                            priv->minor->index,
    108                            is_current_master ? 'y' : 'n',
    109                            priv->authenticated ? 'y' : 'n',
    110                            from_kuid_munged(seq_user_ns(m), uid),
    111                            priv->magic,
    112                            DRM_CLIENT_NAME_MAX_LEN,
    113                            priv->client_name ? priv->client_name : "<unset>");
    114                 rcu_read_unlock();
    115                 mutex_unlock(&priv->client_name_lock);
    116         }
    117         mutex_unlock(&dev->filelist_mutex);
    118         return 0;
    119 }

regards,
dan carpenter