From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1CB63C0032E for ; Wed, 25 Oct 2023 20:02:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:Cc:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+mrf4afshksFohsKnMlMpXZLe+Y0l7OWEiqoAg2X4LI=; b=A3hfrjhc14qnYr KltNIfSx5AGfzhkoKgj0s0t/weBBq2wDgceQTYViqeCug4GK07yjcnEjl6t/QnVDIArRiUJfL0yX6 IbxmIlPLdhxcROiL7dN78PerHHQrKu9/380pyoNNQpeIVdqVll4HWX+LiPm/uUtmvoRQKP9Yxgs5s ryGfuvbz+t8mDSgXY6doJXc/wcqGn/tbU/1bBqCAM7XCEkkV+uOXcavagPzis7P6el6D3xhNnXcXc myUaYMdSUihodpff3SjVTiFxCQt9pu/jaEkKfDf3ETlxgeKGYharA5pcEZIwL4Niku3ZMcXPYNF5f hQyE+KcX9/FyQ/HoC0jA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qvk5P-00D0Q5-2R; Wed, 25 Oct 2023 20:02:39 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:242:246e::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qvk5N-00D0NJ-1A for linux-um@lists.infradead.org; Wed, 25 Oct 2023 20:02:38 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=djw/RRwrhOxPrgNjShiS6oN+TeWC1Dv3drvGlxrWCb0=; t=1698264157; x=1699473757; b=SlfArgRyZWQBTEg4hcaxsS/v9ZJFFsZE8IKXqk212vAR+RR WMiU6uoyAKaVj7ns0sOcKmNmQLHgMNOJoZzG5U0flbdFbjjfJnRclPEpnu+NVo7kxwl4esr8+BZrY 9/6jQr8VvAf/s4e2nd2o9Br1n4nl8JOJtip7ARsEfyBLFyJs8AVC6csxdnQ7K/Cr7qJ4zZ1D9xQx9 FCcyn9MqWHRuUU/77HEw06SUsVtF/R0co3LFAU0g9FsjHY3HQXH0ewtTWvtIxxTxC+oqRePol4TcO D0mjNB8Q9h40m5zvHdP4vfYmvrDFuwGHtBahIStIQv5r3nftBHNlEtm0nioUp4hw==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97-RC1) (envelope-from ) id 1qvk5K-00000002hhp-36fu; Wed, 25 Oct 2023 22:02:34 +0200 Message-ID: <68b18065d8be905c25522bd3f5a9b46dbe3a976d.camel@sipsolutions.net> Subject: Re: [PATCH] um: time-travel: fix time going backwards From: Johannes Berg To: Vincent Whitchurch , "anton.ivanov@cambridgegreys.com" , "richard@nod.at" Cc: "linux-um@lists.infradead.org" , "linux-kernel@vger.kernel.org" , kernel Date: Wed, 25 Oct 2023 22:02:33 +0200 In-Reply-To: References: <20231020-uml-time-backwards-v1-1-90b776fc6dfd@axis.com> <4a75c40636be267163dc30b5a6a2442089628e57.camel@axis.com> <4dbed8896c94a347dcb58b3a83792c52fdc1c04a.camel@sipsolutions.net> User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-malware-bazaar: not-scanned X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231025_130237_397280_9EF9BCC8 X-CRM114-Status: GOOD ( 11.29 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Wed, 2023-10-25 at 21:51 +0200, Johannes Berg wrote: > On Wed, 2023-10-25 at 11:55 +0000, Vincent Whitchurch wrote: > > On Mon, 2023-10-23 at 09:33 +0200, Johannes Berg wrote: > > > Do you have a specific workload that tends to reproduce this? > > > > I've been seeing it when running roadtest, but it's easily reproducible > > without that by using the attached config and the following program as > > init. > > > > cp repro.config .config > > make ARCH=um olddefconfig all > > gcc -Wall -static -o repro repro.c > > ./linux time-travel init=$PWD/repro rootfstype=hostfs Ohhh. Pure "time-travel" is actually something I hardly think about these days, we mostly use time-travel=inf-cpu (or =ext). That makes sense, here you actually *can* get interrupted. I'll need to dig into what happens though. johannes _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um