pidfs: add some CONFIG_DEBUG_VFS asserts

Allow to catch some obvious bugs.

Link: https://lore.kernel.org/20250618-work-pidfs-persistent-v2-16-98f3456fd552@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/pidfs.c b/fs/pidfs.c
index bde19614ef8bace308c7d6d4de3649ec635f8aac..ba526fdd4c4d6cb82397268c55bdf8b9daf0e0a2 100644 (file)
--- a/fs/pidfs.c
+++ b/fs/pidfs.c
@@ -809,6 +809,8 @@ static struct dentry *pidfs_fh_to_dentry(struct super_block *sb,
        if (ret < 0)
                return ERR_PTR(ret);
 
+       VFS_WARN_ON_ONCE(!pid->attr);
+
        mntput(path.mnt);
        return path.dentry;
 }
@@ -1038,6 +1040,8 @@ struct file *pidfs_alloc_file(struct pid *pid, unsigned int flags)
        if (ret < 0)
                return ERR_PTR(ret);
 
+       VFS_WARN_ON_ONCE(!pid->attr);
+
        flags &= ~PIDFD_STALE;
        flags |= O_RDWR;
        pidfd_file = dentry_open(&path, flags, current_cred());