From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 4 Sep 2000 12:54:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 4 Sep 2000 12:54:22 -0400 Received: from [10.0.0.145] ([10.0.0.145]:49416 "EHLO dukat.scot.redhat.com") by vger.kernel.org with ESMTP id ; Mon, 4 Sep 2000 12:54:13 -0400 Date: Mon, 4 Sep 2000 17:07:39 +0100 From: "Stephen C. Tweedie" To: "Theodore Ts'o" Cc: Stephen Tweedie , linux-kernel@vger.kernel.org Subject: Two VM problems for the 2.4 TODO list Message-ID: <20000904170739.I12913@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Ted, To be fixed for 2.4: 1) Non-atomic pte updates The page aging code and mprotect both modify existing ptes non-atomically. That can stomp on the VM hardware on other CPUs setting the dirty bit on mmaped pages when using threads. 2.2 is vulnerable too. 2) RSS locking swapout holds the page_table_lock while swapping, and adjusts the mm->rss while holding that lock. Other places in the mm are not so careful about holding the lock, so rss (which is not an atomic_t) can be corrupted. --Stephen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/