From owner-freebsd-bugs@FreeBSD.ORG Mon Feb 16 21:40:02 2009 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B056F106566C for ; Mon, 16 Feb 2009 21:40:02 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 8AFD28FC0A for ; Mon, 16 Feb 2009 21:40:02 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.3/8.14.3) with ESMTP id n1GLe2Zn082836 for ; Mon, 16 Feb 2009 21:40:02 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.3/8.14.3/Submit) id n1GLe233082835; Mon, 16 Feb 2009 21:40:02 GMT (envelope-from gnats) Resent-Date: Mon, 16 Feb 2009 21:40:02 GMT Resent-Message-Id: <200902162140.n1GLe233082835@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Jari Kirma Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B701910656D1 for ; Mon, 16 Feb 2009 21:38:17 +0000 (UTC) (envelope-from nobody@FreeBSD.org) Received: from www.freebsd.org (www.freebsd.org [IPv6:2001:4f8:fff6::21]) by mx1.freebsd.org (Postfix) with ESMTP id A43B78FC22 for ; Mon, 16 Feb 2009 21:38:17 +0000 (UTC) (envelope-from nobody@FreeBSD.org) Received: from www.freebsd.org (localhost [127.0.0.1]) by www.freebsd.org (8.14.3/8.14.3) with ESMTP id n1GLcHtk069500 for ; Mon, 16 Feb 2009 21:38:17 GMT (envelope-from nobody@www.freebsd.org) Received: (from nobody@localhost) by www.freebsd.org (8.14.3/8.14.3/Submit) id n1GLcHsb069499; Mon, 16 Feb 2009 21:38:17 GMT (envelope-from nobody) Message-Id: <200902162138.n1GLcHsb069499@www.freebsd.org> Date: Mon, 16 Feb 2009 21:38:17 GMT From: Jari Kirma To: freebsd-gnats-submit@FreeBSD.org X-Send-Pr-Version: www-3.1 Cc: Subject: kern/131753: kernel panic in hfsc_dequeue X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Feb 2009 21:40:03 -0000 >Number: 131753 >Category: kern >Synopsis: kernel panic in hfsc_dequeue >Confidential: no >Severity: serious >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon Feb 16 21:40:02 UTC 2009 >Closed-Date: >Last-Modified: >Originator: Jari Kirma >Release: 7.1-STABLE >Organization: Helsinki University of Technology >Environment: FreeBSD xxx 7.1-STABLE FreeBSD 7.1-STABLE #17: Sat Jan 31 12:09:54 EET 2009 xxx@xxx:/usr/obj/usr/src/sys/XXX i386 >Description: System (four-core Intel Q6600 with SMP kernel) crashes under load (although relatively light load, thanks to only 2 Mbit outbound link) of roughty hundred TCP connections somewhat reproducibly when HFSC ALTQ traffic scheduling is used. Only information seen about this is the dmesg message: Fatal trap 12: page fault while in kernel mode cpuid = 0; apic id = 00 fault virtual address = 0x4 fault code = supervisor read, page not present instruction pointer = 0x20:0xc04641e7 stack pointer = 0x28:0xe719ca68 frame pointer = 0x28:0xe719caac code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, def32 1, gran 1 processor eflags = interrupt enabled, resume, IOPL = 0 current process = 15 (swi4: clock sio) trap number = 12 panic: page fault Where the instruction pointer points to inlined code inside hfsc_dequeue: (gdb) l *(0xc04641e7) 0xc04641e7 is in hfsc_dequeue (altq_classq.h:113). 108 struct mbuf *m, *m0; 109 110 if ((m = qtail(q)) == NULL) 111 return (NULL); 112 if ((m0 = m->m_nextpkt) != m) 113 m->m_nextpkt = m0->m_nextpkt; 114 else 115 qtail(q) = NULL; 116 qlen(q)--; 117 m0->m_nextpkt = NULL; Could it be just a simple locking issue in the linked list? >How-To-Repeat: Exact conditions are not known, but running lots of outbound TCP traffic over HFSC connection on a SMP system might trigger it. >Fix: >Release-Note: >Audit-Trail: >Unformatted: