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 30470C4332F for ; Fri, 10 Nov 2023 16:39:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version:Content-Type: References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pytg6vdVo4ro+G3sVuvzRNz3oHzZUvUntWE9Pkjxy6E=; b=oZ4LMWb9mcUMEbDQTQBmuxPIda moiDqWZ2tZtui1RISlTOfyoFo/h7uxThd5ZPAVRoLvfBV1i5T329of47p8o+2wK7ry8EKFhGo2GWQ eVlvCfx/YuQ871r+Wq6Mfd76yTPco0wB/E+kbQ73aMD6+Hs4vvG2zyGp/JQiJ9JDWhgTWpBLUKRJI jAGJUtrKNeLsTqgb995XqTFJ73ysM3w8z/yDAyIj5D8FXqD6BtleCSf5R2ApFE6MHwe8SvhL0pBVk kewjd/lgXA+MzF/NVjWYKsrPV9xBIdc2JfgAVwxlyXyvkxEyV8Qd61f+RqEtXurUPnFxjvW6w95oT SmKjxJ0w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1r1UY2-0095nY-0o; Fri, 10 Nov 2023 16:39:58 +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 1r1UXy-0095mw-2A for linux-um@lists.infradead.org; Fri, 10 Nov 2023 16:39:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Content-Transfer-Encoding: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-To:Resent-Cc:Resent-Message-ID; bh=tAje5/jvw70Jy4s1mJSaED5YleWazOG5O4JAQLxDU04=; t=1699634390; x=1700843990; b=QRFvgQo8aepXup8KdoSvHC6a7QcXt68yyHr0ToksyCJRu9bo5RSVSHS6g++5yhki+BqnL4WovO4 8onnehVwOFWUbInGr81yDb466b19AO9lK8Cg+4ZA7VN3xyMOyhDz1K5Oni0aIc1bKkiNyyauzNBcw G/CG6uC7Hyol5Rtj2i30eZaSXhdmVVOyFBGwgzHPM0appeaYDD0+LkT+1ScVgbYClIqDd1fizESN7 SQR22WLkj7uq8HvZWTjJN6lxKsU0UaRfxL4FDJYULjOW6aluFBu2qkqito0me1RbcvOSc/g/+XPMc aLZCM/KpzffNuigEHlHaGj70ZGtBiHhZfb+w==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97) (envelope-from ) id 1r1UXl-000000035ec-1KQU; Fri, 10 Nov 2023 17:39:41 +0100 Message-ID: <0246e8d9dbccf86a2e83560cc62c0d4b752c7c25.camel@sipsolutions.net> Subject: Re: [PATCH RFC 10/11] um: Delay timer_read only in possible busy loops in TT-mode From: Benjamin Berg To: Benjamin Beichler , Johannes Berg , Richard Weinberger , Anton Ivanov Cc: linux-um@lists.infradead.org Date: Fri, 10 Nov 2023 17:39:39 +0100 In-Reply-To: <867df5dc-8e78-48de-aa1a-da7c8fedb5e6@uni-rostock.de> References: <20231103-bb-timetravel-patches-v1-0-e2c68efcf664@uni-rostock.de> <20231103-bb-timetravel-patches-v1-10-e2c68efcf664@uni-rostock.de> <7daf6651289bd6b48e069f4d0dd7751244177a44.camel@sipsolutions.net> <867df5dc-8e78-48de-aa1a-da7c8fedb5e6@uni-rostock.de> Content-Type: multipart/mixed; boundary="=-wQNp8qjQHojR5UQncRFW" User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-malware-bazaar: not-scanned X-malware-bazaar-2: OK X-malware-bazaar-3: OK X-malware-bazaar-4: OK X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231110_083954_868497_B8661315 X-CRM114-Status: GOOD ( 28.79 ) 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: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org --=-wQNp8qjQHojR5UQncRFW Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2023-11-10 at 16:54 +0100, Benjamin Beichler wrote: > At the moment, we haven't patched the random device that fetches random= =20 > bytes from the host (do you already have a patch for this?), > so complete repeatability isn't guaranteed at the moment. However, that= =20 > could be a logical next step. Right, we have the attached kernel patches internally. This simply disables some of the random sources and replaces os_getrandom with returning static random from the UML_RANDOM environment variable. I doubt that it makes sense to upstream these patches, but may we can include them as patch files in USFSTL or so. The second piece is using a mount namespace to ensure that the linux command line is identical between runs and that the location of all files that are accessed directly from the host through hostfs never changes. The last piece was setting GLIBC_TUNABLES=3D-AVX512CD in the environment just in case the CPU feature set is slightly different. That would cause ld.so to search for a different set of optimized library versions (affecting syscalls and with that randomness). 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charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um --=-wQNp8qjQHojR5UQncRFW--