From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56407) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a7MkS-0001DI-FO for qemu-devel@nongnu.org; Fri, 11 Dec 2015 07:24:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a7MkP-0005N2-9R for qemu-devel@nongnu.org; Fri, 11 Dec 2015 07:24:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57923) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a7MkP-0005Lf-4M for qemu-devel@nongnu.org; Fri, 11 Dec 2015 07:24:29 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 399EBC0C0F9B for ; Fri, 11 Dec 2015 12:24:28 +0000 (UTC) From: Juan Quintela In-Reply-To: <1449765106-6528-1-git-send-email-dgilbert@redhat.com> (David Alan Gilbert's message of "Thu, 10 Dec 2015 16:31:46 +0000") References: <1449765106-6528-1-git-send-email-dgilbert@redhat.com> Date: Fri, 11 Dec 2015 13:24:25 +0100 Message-ID: <874mfpmava.fsf@emacs.mitica> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH] Fix xbzrle vs last_sent_block update Reply-To: quintela@redhat.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert (git)" Cc: amit.shah@redhat.com, qemu-devel@nongnu.org "Dr. David Alan Gilbert (git)" wrote: > From: "Dr. David Alan Gilbert" > > My fix (84e7b80a) replaced the last_sent_block update that I'd > removed earlier; however it was too aggressive in the xbzrle case. > > save_xbzrle_page might return '0' to mean that the page didn't > need sending since it was the same as the last sent version; > in this case we can't update 'last_sent_block' since we didn't > actually send it. > > Symptom: 'Illegal RAM offset 1018000' as we try and send a page > to the wrong RAMBlock; potentially that could be a data > corruption if you were really unlucky. > > Fixes: 84e7b80a05c0c44b90533c6cd2f1db5c932ccf77 > > Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela