binfmt_misc: avoid pointless cred reference count bump

file->f_cred already holds a reference count that is stable during the
operation.

Link: https://lore.kernel.org/r/20241125-work-cred-v2-11-68b9d38bb5b2@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

fs/binfmt_misc.c

@@ -829,9 +829,9 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
 		 * didn't matter much as only a privileged process could open
 		 * the register file.
 		 */
-		old_cred = override_creds(get_new_cred(file->f_cred));
+		old_cred = override_creds(file->f_cred);
 		f = open_exec(e->interpreter);
-		put_cred(revert_creds(old_cred));
+		revert_creds(old_cred);
 		if (IS_ERR(f)) {
 			pr_notice("register: failed to install interpreter file %s\n",
 				 e->interpreter);