From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: Hopefully a simple question on /proc/pid/mem References: <20010430225802.H26638@redhat.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: 30 Apr 2001 19:13:53 -0600 In-Reply-To: "Stephen C. Tweedie"'s message of "Mon, 30 Apr 2001 22:58:02 +0100" Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: "Stephen C. Tweedie" Cc: "Benjamin C.R. LaHaise" , Alexander Viro , Richard F Weber , linux-mm@kvack.org List-ID: "Stephen C. Tweedie" writes: > Hi, > > On Mon, Apr 30, 2001 at 03:02:40PM -0400, Benjamin C.R. LaHaise wrote: > > On Mon, 30 Apr 2001, Alexander Viro wrote: > > > > > I wonder what's wrong with reading from /proc//mem, though - it's > > > using the same code as ptrace. > > > > We can actually do this cleanly now that we have proper page_dirty > > semantics for raw io. The original reason for disabling /proc/*/mem was > > that it left big gaping holes in the mm code in 2.0, and it hasn't been > > repaired since. > > It was mmap of /proc/*/mem which was busted. read/write should be OK. > > Hint: think about what happens if you make a shared mapping of a > private proc/*/mem region... Now that we have reusable swap cache pages we could make it work correctly, except for the case of the first write a private mapping of file. Not that we would want to... Eric -- 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.eu.org/Linux-MM/