From owner-freebsd-bugs@freebsd.org Thu Jun 4 00:28:53 2020 Return-Path: Delivered-To: freebsd-bugs@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 1346B2F8996 for ; Thu, 4 Jun 2020 00:28:53 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 49cmq85sYFz48Yk for ; Thu, 4 Jun 2020 00:28:52 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id C77142F87DB; Thu, 4 Jun 2020 00:28:52 +0000 (UTC) Delivered-To: bugs@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 C732D2F8917 for ; Thu, 4 Jun 2020 00:28:52 +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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49cmq84yVnz48ST for ; Thu, 4 Jun 2020 00:28:52 +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 A5972167F5 for ; Thu, 4 Jun 2020 00:28:52 +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 0540SqPS001495 for ; Thu, 4 Jun 2020 00:28:52 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 0540Sqoe001481 for bugs@FreeBSD.org; Thu, 4 Jun 2020 00:28:52 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: bugs@FreeBSD.org Subject: [Bug 243225] "mpr0: Out of chain frames" boot hang after clang 9.0.1 import (probably timing, not compiler related) Date: Thu, 04 Jun 2020 00:28:52 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 12.0-STABLE X-Bugzilla-Keywords: regression X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: terry-freebsd@glaver.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@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-bugs@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Jun 2020 00:28:53 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D243225 --- Comment #5 from Terry Kennedy --- (In reply to Warner Losh from comment #4) I tried increasing it and it doesn't help. This happens during the initial device probe at boot time. We should only need chain frames if we're doing = I/O to a connected peripheral, and this error happens even without the tape dri= ve (or anything else) connected. Changing the slot the controller is in, enabling/disabling hyperthreading, or sometimes just sitting at the loader prompt before proceeding will make the problem disappear. My guess is that = it is a timing loop that is close to marginal, depending on the other hardware= in the system. When the problem manifests, the system goes down the rabbit hol= e of "out of chain frames", probably because the code thinks the only reason for= an error in that part of the path is running out of chain frames. This is a Dell R730 (complete description in prior reply) so I can capture = the complete boot as a video and make the video (and player app) available if anyone wants to look at it. Alternatively, I can provide remore access (console, reset, etc) via the Dell iDRAC controller. The problem has persisted from 12.0 to the latest 12-STABLE. All hardware is up-to-date, Dell has replaced the controller multiple times and the tape dr= ive and cable once. --=20 You are receiving this mail because: You are the assignee for the bug.=