From owner-freebsd-bugs@freebsd.org Sat Apr 14 19:59:39 2018 Return-Path: Delivered-To: freebsd-bugs@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 8BB24F956E4 for ; Sat, 14 Apr 2018 19:59:39 +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 1C75C86B38 for ; Sat, 14 Apr 2018 19:59:39 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id D1B43F956D6; Sat, 14 Apr 2018 19:59:38 +0000 (UTC) Delivered-To: bugs@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 BDE2AF956CE for ; Sat, 14 Apr 2018 19:59:38 +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 558AD86B17 for ; Sat, 14 Apr 2018 19:59:38 +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 97D8D2585D for ; Sat, 14 Apr 2018 19:59:37 +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 w3EJxbh7063516 for ; Sat, 14 Apr 2018 19:59:37 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w3EJxb9o063515 for bugs@FreeBSD.org; Sat, 14 Apr 2018 19:59:37 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 227285] File descriptor passing does not work reliably on SMP system Date: Sat, 14 Apr 2018 19:59:37 +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 Some People X-Bugzilla-Who: jan.kokemueller@gmail.com X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: attachments.created 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: 2.1.25 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 14 Apr 2018 19:59:39 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D227285 --- Comment #7 from Jan Kokem=C3=BCller --- Created attachment 192515 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D192515&action= =3Dedit patch for a GC that detects cycles I've tried to modify the GC so that it detects cycles in all "in flight" sockets and only destroys sockets that are in such a cycle. With this patch= the test program doesn't exit anymore. I wonder if there can be false negatives with a GC that just detects cycles. DragonFly has some interesting comments[1]. DragonFly still suffers from th= is race, though. It looks like Linux had the same race when they still used a mark & sweep GC instead of a cycle detecting one. Search for "rewrite AF_UNIX garbage collector". The BUGS section in the man page for send(2) looks related to this problem. This seems to be a long standing issue. [1]: https://github.com/DragonFlyBSD/DragonFlyBSD/blob/b9f81f6ad2f9ae32fb3ec268a= 1ea2edac10f373e/sys/kern/uipc_usrreq.c#L72 --=20 You are receiving this mail because: You are the assignee for the bug.=