From owner-freebsd-bugs@FreeBSD.ORG Fri Feb 27 14:40:04 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 2708A1065680 for ; Fri, 27 Feb 2009 14:40:04 +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 029CA8FC1A for ; Fri, 27 Feb 2009 14:40:04 +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 n1REe3eM026337 for ; Fri, 27 Feb 2009 14:40:03 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.3/8.14.3/Submit) id n1REe3Vl026336; Fri, 27 Feb 2009 14:40:03 GMT (envelope-from gnats) Resent-Date: Fri, 27 Feb 2009 14:40:03 GMT Resent-Message-Id: <200902271440.n1REe3Vl026336@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, Matthew West Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E8B52106564A for ; Fri, 27 Feb 2009 14:35:42 +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 D7DBF8FC18 for ; Fri, 27 Feb 2009 14:35:42 +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 n1REZfCw032234 for ; Fri, 27 Feb 2009 14:35:41 GMT (envelope-from nobody@www.freebsd.org) Received: (from nobody@localhost) by www.freebsd.org (8.14.3/8.14.3/Submit) id n1REZfNP032233; Fri, 27 Feb 2009 14:35:41 GMT (envelope-from nobody) Message-Id: <200902271435.n1REZfNP032233@www.freebsd.org> Date: Fri, 27 Feb 2009 14:35:41 GMT From: Matthew West To: freebsd-gnats-submit@FreeBSD.org X-Send-Pr-Version: www-3.1 Cc: Subject: kern/132165: LOR slock and uart_hwmtx 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: Fri, 27 Feb 2009 14:40:04 -0000 >Number: 132165 >Category: kern >Synopsis: LOR slock and uart_hwmtx >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Feb 27 14:40:03 UTC 2009 >Closed-Date: >Last-Modified: >Originator: Matthew West >Release: FreeBSD 8.0-CURRENT amd64 >Organization: >Environment: FreeBSD foo.internal 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Fri Feb 27 12:43:45 GMT 2009 mwest@foo.internal:/usr/obj/usr/src/sys/DEBUGLOCK amd64 >Description: A -CURRENT system built with sources from yesterday, GENERIC kernel except with some extra VFS deadlock debugging enabled. Serial console attached. After a few hours with the system being mostly idle, a LOR was displayed. The system didn't crash, and the serial console continues to work as expected. I couldn't find another report for this, so here you we go: lock order reversal: 1st 0xffffff0004776020 process slock (process slock) @ /usr/src/sys/kern/kern_proc.c:788 2nd 0xffffff000444a238 uart_hwmtx (uart_hwmtx) @ /usr/src/sys/dev/uart/uart_cpu.h:92 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2a _witness_debugger() at _witness_debugger+0x2e witness_checkorder() at witness_checkorder+0x81e _mtx_lock_spin_flags() at _mtx_lock_spin_flags+0x94 uart_cnputc() at uart_cnputc+0x40 cnputc() at cnputc+0x49 putchar() at putchar+0x6a kvprintf() at kvprintf+0x81 printf() at printf+0xa4 calcru1() at calcru1+0x1a0 calcru() at calcru+0xda fill_kinfo_proc() at fill_kinfo_proc+0x5f8 sysctl_out_proc() at sysctl_out_proc+0x7d sysctl_kern_proc() at sysctl_kern_proc+0x228 sysctl_root() at sysctl_root+0xe3 userland_sysctl() at userland_sysctl+0x11c __sysctl() at __sysctl+0xaa syscall() at syscall+0x1e7 Xfast_syscall() at Xfast_syscall+0xab --- syscall (202, FreeBSD ELF64, __sysctl), rip = 0x8009431fc, rsp = 0x7fffffffda08, rbp = 0xffffdb01 --- >How-To-Repeat: >Fix: >Release-Note: >Audit-Trail: >Unformatted: