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 F0D56C07545 for ; Wed, 25 Oct 2023 20:41:44 +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=BV8Hbda150urOvVHef1hty41/AMR85+HSsaBO6JtC1Y=; b=Clq7tlrMxvNYeU bHMzwW/5HyU8Sg92P1+p+DekpPzxw34vTSf8VRpY4d2a/O8rmX/AUAnJyuJpStTrGnOhuUmb8zRBN 9bXgr65AYMuIIy+ZXEiQyOa2TfcyRi0g7UkgFCJ6GdZMkOx7PBbgMkysRvnxW64SyL4iAqM2Q8sJC ki5Gblb7rmAeZ1L49mo7CoodRRA0i5ZD1dHVJwwG8ba3vNY6FskX+RnAxkKEu/XS/MLkAtge5V/wO cH2HXHyv40gcUoOTm7MaMvyYQKYmUq5yL1dW3+y4t455ze+UWbgXJbloAgZ2cs7mefF/jipasTHJu n3gBaBSZWdHPih+0NQhw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qvkhD-00D6S5-3C; Wed, 25 Oct 2023 20:41:43 +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 1qvkhB-00D6R5-22 for linux-um@lists.infradead.org; Wed, 25 Oct 2023 20:41:42 +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=DsYdjSLqGrd7t0Y6Nn+QoZo/dHfV0hHOlcoK0gUrZCY=; t=1698266501; x=1699476101; b=kDmH0azXB7nUe1H+herAA2UDWRUX+ophhZx0B/qZI10fFcl wxbN4rU9CMGW1Hpmv/coN6eQtR2eiKvlYlAiTsALBvaCFQENHYfDoYz48iykvVoHeuOnisI66Xado 6yzAyqYZ/vivLBftlk6bfPBNpTmF2yH++JyWGxiWWBLK3sXH0fmiwLQp3x/8Eb4JwKf/tsIpE1bDf BFO1gaQT1DqQ2pwmj+iSTc3j0cRiDBPz05tune3yGbmBd8ofJ8g/IKNceJzzEB2ZJ/EjKuSKCK3iE AYvf3vReJNU0uEko972I+WQorf7i+hEnX+r0+ClA4J8NB+ag3ftJqJ5gfB3bf0nQ==; 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 1qvkh9-00000002iVb-0Mrm; Wed, 25 Oct 2023 22:41:39 +0200 Message-ID: <1f38d92435cc4f3a5e8d17dff3da9e34be2e6f24.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 22:41:38 +0200 In-Reply-To: <68b18065d8be905c25522bd3f5a9b46dbe3a976d.camel@sipsolutions.net> References: <20231020-uml-time-backwards-v1-1-90b776fc6dfd@axis.com> <4a75c40636be267163dc30b5a6a2442089628e57.camel@axis.com> <4dbed8896c94a347dcb58b3a83792c52fdc1c04a.camel@sipsolutions.net> <68b18065d8be905c25522bd3f5a9b46dbe3a976d.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_134141_672304_69743262 X-CRM114-Status: GOOD ( 14.98 ) 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 22:02 +0200, Johannes Berg wrote: > 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. I just sent a patch, please take a look. It does seem to fix it - at least I got bored of waiting after running your test program for a few minutes :) johannes _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um