From owner-freebsd-transport@freebsd.org Fri Mar 5 17:35:20 2021 Return-Path: Delivered-To: freebsd-transport@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 02A03560CA9 for ; Fri, 5 Mar 2021 17:35:20 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (unknown [127.0.1.3]) by mx1.freebsd.org (Postfix) with ESMTP id 4DsZd36VKXz4vbr for ; Fri, 5 Mar 2021 17:35:19 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id DEF58560CA8; Fri, 5 Mar 2021 17:35:19 +0000 (UTC) Delivered-To: transport@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 DEBD65609CA for ; Fri, 5 Mar 2021 17:35:19 +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 4DsZd35v7sz4vQB for ; Fri, 5 Mar 2021 17:35:19 +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 B9B32142EB for ; Fri, 5 Mar 2021 17:35:19 +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 125HZJEk003257 for ; Fri, 5 Mar 2021 17:35:19 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 125HZJbs003256 for transport@FreeBSD.org; Fri, 5 Mar 2021 17:35:19 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: transport@FreeBSD.org Subject: [Bug 253848] [tcp] panic: sackhint bytes rtx >= 0 Date: Fri, 05 Mar 2021 17:35:20 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 13.0-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: rscheff@freebsd.org X-Bugzilla-Status: Closed X-Bugzilla-Resolution: FIXED X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: rscheff@freebsd.org X-Bugzilla-Flags: 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 MIME-Version: 1.0 X-BeenThere: freebsd-transport@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Discussions of transport level network protocols in FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Mar 2021 17:35:20 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D253848 --- Comment #6 from Richard Scheffenegger --- It turned out that only under a specific set of circumstances - RTO during a SACK loss recovery, while the client had not yet fully reported back all SA= CK blocks - a unnecessary initialization of sack_bytes_rexmit caused this pani= c.=20 In mundane environments this was virtually not reproduceable, and even in exposed environments, tcp sessions apparently need to suffer from sudden RTT jumps / path changes to elicit the panic. Thanks to rrs@ and gallatin@ for helping by providing crucial timing and pa= cket trace/tcp state information around a few occurances. --=20 You are receiving this mail because: You are on the CC list for the bug.=