From owner-freebsd-fs@freebsd.org Tue Feb 12 00:27:03 2019 Return-Path: Delivered-To: freebsd-fs@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 64D6514E83BA for ; Tue, 12 Feb 2019 00:27:03 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id CE92890902 for ; Tue, 12 Feb 2019 00:27:02 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 7F6E314E83B8; Tue, 12 Feb 2019 00:27:02 +0000 (UTC) Delivered-To: fs@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 5878B14E83B5 for ; Tue, 12 Feb 2019 00:27:02 +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 TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id E3F49908FE for ; Tue, 12 Feb 2019 00:27:01 +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 202EE24FBC for ; Tue, 12 Feb 2019 00:27:01 +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 x1C0R1sr032177 for ; Tue, 12 Feb 2019 00:27:01 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id x1C0R0TQ032171 for fs@FreeBSD.org; Tue, 12 Feb 2019 00:27:00 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: fs@FreeBSD.org Subject: [Bug 235582] rpc_svc_gss / nfsd kernel panic Date: Tue, 12 Feb 2019 00:27:00 +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: 11.2-RELEASE X-Bugzilla-Keywords: panic X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: rmacklem@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: fs@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-fs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Feb 2019 00:27:03 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D235582 --- Comment #20 from Rick Macklem --- Well, if you have NFS client(s) mounted with more than CLIENT_MAX different users actively using the mount concurrently, that might tickle the race? - Basically, this code (which handles a new credential creation) happens when there is a miss on the cache of credentials (which is capped at CLIENT_MAX), where each distinct user (as in uid) would need a credential. --> Conversely, making CLIENT_MAX >=3D the maximum # of different uids acti= vely using the file system might reduce the likelyhood of the crash, since t= his code would be executed less frequently. Related to Ben's comment (thanks for the nice description of the name): - It did tickle a rusty brain cell. I think I was confusing gss_export_name= () with gss_display_name(). Unfortunately, this isn't very useful, since neither gss_display_name() nor gss_localname() are supported by the KGSSAPI. If you search for "_svc" in usr.sbin/gssd/gssd.c, you'll see the rather small list of gssapi functions supported by the KGSSAPI (unless I've misread this code). - I think the structure is called "Principal" (also called "krb5_principal_data"). It seems to be defined in krb5_asn1.h and that isn't in the kernel either. --> I suspect this is why the logging code enabled via compiling it with DEBUG defined just logs the output of gss_export_name() and doesn't try and extract the components of it? Good luck with your testing, rick --=20 You are receiving this mail because: You are the assignee for the bug.=