From nobody Thu Sep 22 08:45:01 2022 X-Original-To: net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4MY8412W6Rz4cnfS for ; Thu, 22 Sep 2022 08:45:05 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (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 "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4MY8411TxMz3gPw for ; Thu, 22 Sep 2022 08:45:05 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (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 did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4MY8410YjqzLtY for ; Thu, 22 Sep 2022 08:45:05 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 28M8j5LI071907 for ; Thu, 22 Sep 2022 08:45:05 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 28M8j5Oi071906 for net@FreeBSD.org; Thu, 22 Sep 2022 08:45:05 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 264257] [tcp] Panic: Fatal trap 12: page fault while in kernel mode (if_io_tqg_4) - m_copydata ... at /usr/src/sys/kern/uipc_mbuf.c:659 Date: Thu, 22 Sep 2022 08:45:01 +0000 X-Bugzilla-Reason: CC AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 13.1-RELEASE X-Bugzilla-Keywords: crash, needs-qa X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: rscheff@freebsd.org X-Bugzilla-Status: Open X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: net@FreeBSD.org X-Bugzilla-Flags: maintainer-feedback? maintainer-feedback? maintainer-feedback- maintainer-feedback? mfc-stable13? X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1663836305; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1k1+FgH1QJUiaq4lKoIQHuHBEni90wet+DXGpwr33uA=; b=ye+P+mOiF/UwcPXHWSfgoY0GcpepqgGmlBPiLpSK3RUEo6XToxUCokPo1VV7yFI5VNp4ta b5WDDr37LzYauBcZ9bwDp/cL7Z+rM6Z954jojU6T3/xPCmnv+Vgi1ubQxDS3l2jB10yS8E bKk6IHv3PGbg3L8OMFhXIGV39pTkEjMEy6f4IMrc3YR6gmHM47N9FH/bk848uFt1tKSoXE nE4wlQce/pCR6mwLeKJAEdoH18JWwdr6SDb3AU3DgHQV2Fxt+MNaLYCVCiY7kNIDn4wpsG FYdrHOHxx4PD7IJgS/GXpoi2v8JhSDQYlt3d39kMWspKTqOg3tGnG1h1olWPVQ== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1663836305; a=rsa-sha256; cv=none; b=ndfi+JFETQwCqHorSh6+Afc6xcBUD9YYiZCxgPqMkUgOxSoPPfI4dxZGVLzgHtrO6bQpmM ZESCzk7z/LWdzrXCqBKghyU7dg1fiLs35Uc/NuMP0TyvkTKP2506SYL2BOK8+4caKjtzK4 hN/PDtL04hZAa5frGCz4nU0qMFrivrhi0x8ymcOiwbWeJ4zvSraqsc5lts0eFHIekSjMp8 HY+4LgQygYxWOGF33xOJgsgxrAov+HEAuSKW4kzvFMEIOFi6aLG/9TnVfz5sXLWImpIHak DYOjwAOyakzQaE+riGj6VkL0CbP1475/f7VXCB+aIFpXS5Eym68O9547RYpeQg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D264257 --- Comment #99 from Richard Scheffenegger --- (In reply to Marek Zarychta from comment #98) > It looks like setting "net.inet.tcp.rfc6675_pipe=3D1" was a workaround, c= ould you confirm, please? The workaround was "net.inet.tcp.rfc6675_pipe=3D0" for bug 254244, to disab= le "SACK rescue retransmissions". > This issue looks similar to the already fixed bug 254244. Similar yes, but not identical. In Bug 254244, it was an oversight on my part, to deal with the final = bit in the sequence number space, if a rescue retransmission is to be done after the stack had already sent this . The implicit assumption is, that at the tail end of a TCP session, only a single , at one specific sequence number exists - as it should be. However, the complex of bug 260393, bug 263445 and this bug 264257 comes fr= om an issue which existed "forever", but never, or extremely rarely manifested itself as a server-side panic. It does have some potential to lead to erran= eous bytes at the tail end of a tcp session, which, depending on the application using the data, may lead to client side data inconsistencies. That issue is, that under specific circumstances, a TCP session will sent multiple at advancing sequence numbers, and "overwriting" the previou= sly sent with a (not fully) arbitrary data byte. In once instance, logging showed up to 6 consecutive s, each at a new position - but even just two such at consecutive positions are problematic.=20 This day-zero issue (most likely affecting / having affected all BSD derived TCP stacks with active SACK) is fixed in FreeBSD with=20 https://reviews.freebsd.org/D36626 While investigating further, two more bugs showed up: https://reviews.freebsd.org/D36631 https://reviews.freebsd.org/D36637 but these do not corrupt the tcpcb state, or lead to erraneous transmission= of different information at the same sequence number - only affect when and wh= ich segments are sent.=20 (A regression in MAIN was also found during looking closely at the test cas= es - one of which would not fully validate the expected state, but that is not related directly to this problem really). --=20 You are receiving this mail because: You are on the CC list for the bug. You are the assignee for the bug.=