From owner-freebsd-current@freebsd.org Sun Jul 12 22:06:57 2020 Return-Path: Delivered-To: freebsd-current@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 5BF75350407 for ; Sun, 12 Jul 2020 22:06:57 +0000 (UTC) (envelope-from delphij@delphij.net) Received: from anubis.delphij.net (anubis.delphij.net [IPv6:2001:470:1:117::25]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "anubis.delphij.net", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4B4gqN27Ffz46PJ for ; Sun, 12 Jul 2020 22:06:55 +0000 (UTC) (envelope-from delphij@delphij.net) Received: from p51.home.us.delphij.net (unknown [IPv6:2601:646:8600:58ba:e670:b8ff:fe5c:4e69]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by anubis.delphij.net (Postfix) with ESMTPSA id AC0CE45869 for ; Sun, 12 Jul 2020 15:06:54 -0700 (PDT) Reply-To: d@delphij.net To: freebsd-current@freebsd.org References: <20200712033332.GA63411@www.zefox.net> <20200712072911.GG4213@funkthat.com> From: Xin Li Autocrypt: addr=delphij@delphij.net; keydata= mQINBFuSR4oBEACvvEgwRIHs6IcSP/yaDtySF78Ji3rP29qdiQsxhMsOtvtffdbS56VApIWO UFb3/iN2gA8HwLvrmjijN0HEoLVX7na1WARmxRYzQMtApsZIUTtx7hnUYlsi2F5odZa6CDW9 a954DLRzYxiUwYDcu5Zjl9bglK1H8e/N9uC0Vuigr4teWfh86brzOyf819QzwFVYfMIK4ihw QGwMvTzbyVuCFy+LENkmcVYni70oQy6rZ5ktSuYbuOFvu7inRRfhSWPHziV7k+bW88sJ7xhv lBlegcnhkSudWX2M8tZ3MO1PJOcyys0CJlsBY5Weiog2lIPi05h/E9pZ9mc1Vud17iqDaL6w RaggOUhuPfDGCdO5ro82W4BZGeQMRnRF5Ntk+t2ShIH4nn3xRLV0E5nziCiKlgiMqOrz/ZTL QTVbHrCuiwD+fSK14y0oHbkOLYTYLlgh1JbwfY2Ty7elOYiWzyeJ7sJh2dF91NSEneWIOys3 mBpuvtU3nSzzTvAB48VV+Nbg1CpIOgNlPjj7uhIum/Z/VjUaJEyaLpTIRh0MVJVcbP7hXSqZ NA35EEZZVnWEOYdycm4CmEdeNPWkrAf2Ya77iR5VLGypwMlsUMQPh+sKVWDD38M8stFGBBNm d01Hi74Bsq5hKan654dOqMt5eYklrVj0ucMzFQtus7oE502UswARAQABtBxYaW4gTEkgPGRl bHBoaWpAZGVscGhpai5uZXQ+iQJUBBMBCgA+FiEEceNg5NEMZIki80nQQHl/fJX0g08FAluS R/YCGwMFCQmuhAAFCwkIBwMFFQoJCAsFFgIDAQACHgECF4AACgkQQHl/fJX0g0+2Og//bWpE F2V5/M5l6YW1T8oLcT9rIOH6oq9M0LMNRgFeiNNnilGIeeIgtOGBRueG4CZiZAvsRPJkrO70 1R2SrdkCIvwGUzUAxx1NfBWb+vgm4fgkW/MotGonceM5v0qfSKKXasWvDctkK28aG+IoQzmi FjXNW4+ju4zeQFYwD4ZDWqw9MqO0hVb24uW3dxtQhbfmOLgJ/PEDMQaFuANbW1c+iR0BQA3D Go/EeMY4kpN8on6Aqt/S/4JVltudfQ9OXdjQsC7netSaB9K3mHGt9aKAAB7RzlRY00DKkYS/ /eQwLzGPmK7yX13M68mMDjBs6mIR8t/E1S5OdBNhHRPNPlEbwugR4KaiCsN5yqzJoSV99fKY z2VyxjWPaG8yhHE+jmKUgIBKTfFUQEfkriQR4EASoeJ+soaMTiFDBij1Zw5n3ndLRFMB1ZCl fZLER36mAgW4m4kP83TWnDiJLxOxSOxifV8HpTFjff902H85cybg9KMwrfPDr6W19GGk5Vo1 fkza5krRMGbKWb7+74Evusi0ZxJLIOFwp5Y8eVqUMZaAD3f1ZX1M3pgXOp20QgAy+2KvMHij rLa4q+tMGRzYYD1BnFVSVdXAX5VOoTmHBcDz67DkuRwk2Byp1sgd407oEOmSwrNJlKS0TPCm xUJ2fdSQF+1/MMSRfee49vtMvz7cOrC5Ag0EW5JHigEQANiBmIFAfRNH3nzYNWC0yC+tfx3z sUwAsH1VaBM/cTib+yKtbBOSIlXWjJZWX3MHwoI/1LeGghB2mxkkX1L0pJ/vj1eXNR+sFZ32 0pYcl61Fxg/5fioG4QDTM4i3i7NR5PxDnc6UVaynSlII93DedRhZ1ROtdn4vyMgzsDiqhbL7 BthDOt5KxjqdRk4qRPSw7BovEqZLOcG5IJtf/zZUzRbM7SBljEbOAfekDGx1Br+RrYSD7/Ef Pwwzou9T8315IpBpIHyQF/dZNk3iFiB9Ed5CA71ZRYV5YoLWE9lL0j9kxOLQ5vHnX3mVq7QZ Bc7nzwZ6UhQgYmrG5+RWvuiPpGwvDRIsugJUGXucYkAQh5kuNblmkwpv6u9rNMjCNbzAylOa qdogra5EW+RUSbRz0b4iIr8nnZeAlh7BihCe7JjOwbDjoBEEEtSfVc4hD/LENqpcYVrChphf aOLB9YIXhnVDTVvMc9OklWT/81HzAaDQqOQCzEfY92199Ct9/CwRoQ2OpO8TO5+8A7b9Nb33 nmxMn09mb48ruRacMrfHxCWbgU4w9SEfbip4GcS5wGG6yTC+hw55Iwnnwus40NrJ0GEr8a4r cdsLbkvlyoNHB8ZGgyJ4aFCQ1V4qE1BnlTk7Z8BYBUkJM1odPSkVvHpCnMUjVpJ3hEOC+73Z YH1dh7lZABEBAAGJAjwEGAEKACYWIQRx42Dk0QxkiSLzSdBAeX98lfSDTwUCW5JHigIbDAUJ Ca6EAAAKCRBAeX98lfSDTz8DEACMh3poeUb+gWNF4RWFZuLteZVo0+E1JLYXQkmtrRBLXviP +Qy0pXyFAVxLM4hNIBoIDYfK9BcwrBYf7AwSKrH0GiNwFpgHCkbZd6qoZy2gB+adTnCpVCTJ KJetsH/8awkrChJWMK0ckGf3EeWMPvawG7kW7FBz70NYEZ0pOMiaEZNVtzD3wwbYWUiDFYth 83XGglOExg+1ShTW5XjQPRrdyJAO+aUW4o3lVjfyUJXMgI4rmhMiLVm06GuNrbpKIF0s+4Vd jQAjhrDQjfoXi9CkfsA/cONseuHNv1JGj3RqHiqHJq1dbrpodXp925zGDAnUGxCOBPoFopAH gVzR89GTut059GpwqsddZmU6y7rqifuam/ekJ+QRwc16vgt7pHqCrTY8WPxRZr2UpFU1wlTo COdeiFep1gq1F9jzFjJnoMaAdmC6k7bgAA+RQusOgIhJL0jIej7DoAHxmxFFCfRy+lDtpXwF gQ8HMvzHI65QWmQnMo7s6SQH/ZH5s1yR6SJq8+3lDz+dCuT42qJVqIPVvxd10LW0FNN+t7HF eLadU6ekSgD13/EYMYXlvNHkw7dAItSDxIzgRyykLz0bCU9xwNWoS4Z43+ifF9anJ+uR0ltW El1j++h6ZrD3LLuCgJIt1so0m49GzdcSpOI7LCwMlacyvafiEyjUn+tSNDsnfw== Organization: The FreeBSD Project Subject: Re: Is there any error checking on swap? Message-ID: Date: Sun, 12 Jul 2020 15:06:49 -0700 MIME-Version: 1.0 In-Reply-To: <20200712072911.GG4213@funkthat.com> Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="LMnbsEF8WeMUkozyo6orSrKHBIwGgugr0" X-Rspamd-Queue-Id: 4B4gqN27Ffz46PJ X-Spamd-Bar: ---- X-Spamd-Result: default: False [-4.07 / 15.00]; HAS_REPLYTO(0.00)[d@delphij.net]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_SPF_ALLOW(-0.20)[+a:sirius.delphij.net]; HAS_ATTACHMENT(0.00)[]; TO_DN_NONE(0.00)[]; HAS_ORG_HEADER(0.00)[]; DKIM_TRACE(0.00)[delphij.net:+]; DMARC_POLICY_ALLOW(-0.50)[delphij.net,reject]; SIGNED_PGP(-2.00)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:+,3:~]; SUBJECT_ENDS_QUESTION(1.00)[]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.02)[-1.022]; R_DKIM_ALLOW(-0.20)[delphij.net:s=m7e2]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-0.98)[-0.984]; MIME_GOOD(-0.20)[multipart/signed,multipart/mixed,text/plain]; REPLYTO_DOM_EQ_FROM_DOM(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-current@freebsd.org]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_SPAM_SHORT(0.04)[0.037]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 Jul 2020 22:06:57 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --LMnbsEF8WeMUkozyo6orSrKHBIwGgugr0 Content-Type: multipart/mixed; boundary="UGCJhs9mWmeFod3EV4IksQZz4eH5wRmpc"; protected-headers="v1" From: Xin Li Reply-To: d@delphij.net To: freebsd-current@freebsd.org Message-ID: Subject: Re: Is there any error checking on swap? References: <20200712033332.GA63411@www.zefox.net> <20200712072911.GG4213@funkthat.com> In-Reply-To: <20200712072911.GG4213@funkthat.com> --UGCJhs9mWmeFod3EV4IksQZz4eH5wRmpc Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 7/12/20 12:29 AM, John-Mark Gurney wrote: > bob prohaska wrote this message on Sat, Jul 11, 2020 at 20:33 -0700: >> Is there any error checking on swap traffic, along the lines of >> a checksum or parity test?=20 >> >> Just curious what happens if a page written out is corrupted when >> it comes back. >=20 > Looks like it doesn't: > https://svnweb.freebsd.org/base/head/sys/vm/swap_pager.c?annotate=3D361= 965#l1389 Technically one can enable checks with e.g. geli(8), but note that the geli(8) provider will not "prime" the HMAC data so attaching the device will immediately spam the system log with some authentication errors due to GEOM tasting (because the kernel would try to read locations that potentially contain metadata for other GEOM providers). For the case of swap, since the write is always page sized, it's probably optimal to implement something in the swap layer itself and store the expected checksums in memory. Cheers, --UGCJhs9mWmeFod3EV4IksQZz4eH5wRmpc-- --LMnbsEF8WeMUkozyo6orSrKHBIwGgugr0 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.2.20 (FreeBSD) iQIzBAEBCgAdFiEEceNg5NEMZIki80nQQHl/fJX0g08FAl8LiX0ACgkQQHl/fJX0 g09xQQ//UXdeg1WXxoi0WQR8Dr1xwLeKUhW+KULfN3wuH0M8feIcVZca033Ra8w4 rMdx9HF7H87vbgUb4Cw1UfcAyLgJSbQ09tV0m3O6NRgI9E9Awfys0vVIOnpvrcI7 R1VTHqYqiI2iKuaxf0aY/YVoMQWXGeP7G45dKUk/jhXC9XfSphhep0xUOacm7cyp W14uIn8mDeEyHCjEByxfuZ3Xefg8cO7hwcgDCRY3qK+Wd3D1hOwRvQkPSbzTyLJA QITqqZFnGbiTTpSO+IIkmFdH+HfvM7R6lZOuNAC7PG0+0neosCG82wRwH2XTzRhz g49dWL+NXheTJhaTQ5CStMZw3dnNafm9nuxLkA2OtHuRsVYmJUHXj9ynRAVJd8dA A/G/6Dk9mtkZW+cIEft0jqmF9iVdv/pPH/efyJaJtarabr8rZztefn8vbZ5P6pKW nAZLcSBdGo1AhVaGEaK9dneQ1mFn7DFsQBjv1gGYPR3TKXXC4GfbZWTLlapiAZ8U BaIYtk6YgR819w21Qk0OBNh+zTLuAxTpwMJo02xOTgPRbIZ9b5hzR+c7MlIULlvY 6mBiB4omc5lqvWRC+8QR/kFXTMxkrghA405uiBwX+z9s8EEdJuOaNm948GqGxW7N Hn4PNyUFyILqiRUGTlUL3jSPq4O3jLl7L+wJ+Y6XFx32qrN8RC8= =cW4G -----END PGP SIGNATURE----- --LMnbsEF8WeMUkozyo6orSrKHBIwGgugr0--