From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx106.postini.com [74.125.245.106]) by kanga.kvack.org (Postfix) with SMTP id 286AA6B0044 for ; Fri, 23 Mar 2012 16:53:58 -0400 (EDT) Date: Fri, 23 Mar 2012 13:53:56 -0700 From: Andrew Morton Subject: Re: [PATCH] swapon: check validity of swap_flags Message-Id: <20120323135356.6b2376d6.akpm@linux-foundation.org> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Al Viro , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Fri, 23 Mar 2012 13:48:35 -0700 (PDT) Hugh Dickins wrote: > Most system calls taking flags first check that the flags passed in are > valid, and that helps userspace to detect when new flags are supported. > > But swapon never did so: start checking now, to help if we ever want to > support more swap_flags in future. > > It's difficult to get stray bits set in an int, and swapon is not widely > used, so this is most unlikely to break any userspace; but we can just > revert if it turns out to do so. It would be safer to emit a nasty message then let the swapon proceed as before. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org