From owner-freebsd-net@freebsd.org Fri Feb 16 10:33:36 2018 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id F1522F0559D for ; Fri, 16 Feb 2018 10:33:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 8DEF7718A6 for ; Fri, 16 Feb 2018 10:33:35 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id C18BD3ACF for ; Fri, 16 Feb 2018 10:33:34 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w1GAXYvT067258 for ; Fri, 16 Feb 2018 10:33:34 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w1GAXYtE067257 for freebsd-net@FreeBSD.org; Fri, 16 Feb 2018 10:33:34 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: freebsd-net@FreeBSD.org Subject: [Bug 225927] [panic] NULL pointer dereference in nd6_llinfo_timer() Date: Fri, 16 Feb 2018 10:33:34 +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: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: ae@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-net@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-net@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Feb 2018 10:33:36 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D225927 --- Comment #4 from Andrey V. Elsukov --- (In reply to Hans Petter Selasky from comment #3) > Can you try the patch in D4605 ? This problem is not easy to trigger and I'm not sure that the patch solves = it. I think how it happens: on ifnet departure in6_domifdetach() is called, then lltable_free() unlinks lltable and acquires LLE_WLOCK for each llentry. While we are acquiring all these locks it is possible, that callout for some entry has been started and blocked on the LLE_WLOCK() since lock is held by lltable_free(). Then llentry_free() releases LLE_WLOCK(), and nd6_llinfo_timer() acquires it. No= w we have invalid ifp pointer, it is strange enough that it is NULL... About your patch, it seems the code: if (callout_stop(&lle->lle_timer) > 0) LLE_REMREF(lle); can be placed in the llentry_free() only once, and also removed from lltable_free(). But it doesn't protect from described scenario. I think we = need somehow handle the case when nd6_llinfo_timer() is already active, but it hasn't obtained lock yet. --=20 You are receiving this mail because: You are the assignee for the bug.=