From owner-freebsd-current@FreeBSD.ORG Fri Jul 27 20:31:55 2012 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 648A3106564A; Fri, 27 Jul 2012 20:31:55 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-pb0-f54.google.com (mail-pb0-f54.google.com [209.85.160.54]) by mx1.freebsd.org (Postfix) with ESMTP id 30C5F8FC0C; Fri, 27 Jul 2012 20:31:55 +0000 (UTC) Received: by pbbro2 with SMTP id ro2so5956057pbb.13 for ; Fri, 27 Jul 2012 13:31:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=nLD1nWiCkAQJIpWcZ9f6MTcGibLlqDbnNPrcb4L7lMQ=; b=j2xSuEKyv548jW/r3mZq9ozBna9sRbzzmiDOa8M5CPxI7s+gKUKbzHDLxUZJhJl2Ar 5i4OOBk/j/OPMv0+on9jA7+eyc/MdA+onZXjn1p2Zf1XLDsSUR0f9OWziY2ME0fLemJ6 mqebON8nt7k9HcNY6iCyKId++Tr4w4yAZ10D/7RnLTV40yOzN8UlbAQXq+bGp3dHt6Gt iG8p8G1+q75qfsJLSLqofWVyE5GdAhHvRxYOslPvtKotmxbAMR9yHlB05CC6EUIHxthY j44roQ1SJiNGZtp4eqZjbmhowrwxvfrLyAeWfa5SIdyzf43lDNWXHXiYRR3Jc/NFtdFd uUUA== MIME-Version: 1.0 Received: by 10.68.203.7 with SMTP id km7mr16867666pbc.7.1343421114803; Fri, 27 Jul 2012 13:31:54 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.68.66.136 with HTTP; Fri, 27 Jul 2012 13:31:54 -0700 (PDT) In-Reply-To: <5012E233.3050007@FreeBSD.org> References: <20120726154610.GC1587@albert.catwhisker.org> <5012E233.3050007@FreeBSD.org> Date: Fri, 27 Jul 2012 13:31:54 -0700 X-Google-Sender-Auth: nLdP9d1E_m7tzBQkoUN99XZrYG0 Message-ID: From: Adrian Chadd To: Dimitry Andric Content-Type: text/plain; charset=ISO-8859-1 Cc: current@freebsd.org Subject: Re: panic: _mtx_lock_sleep: recursed on non-recursive mutex em0 @ /usr/src/sys/dev/e1000/if_lem.c:881 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Jul 2012 20:31:55 -0000 It looks like a case of "lock held during call up the stack". This is bad for so many reasons. It also makes writing correctly locked drivers a pain in the ass as the moment you unlock the driver before calling ether_input() / ieee80211_input(), you allow things to change state. So no, although you shouldn't use long-held locks to protect things, apparently this is all the rage. iwn(4) does this. ath(4) does not. I'm having a right painful time trying to fine-grain lock things. I'm at the point where I'm about to not care, rip out all the locks and replace with a single ATH_LOCK(). Adrian On 27 July 2012 11:47, Dimitry Andric wrote: > On 2012-07-26 17:46, David Wolfskill wrote: >> This is at r238795; cut/paste of backtrace: >> >> KDB: enter: panic >> [ thread pid 12 tid 100026 ] >> Stopped at kdb_enter+0x3d: movl $0,kdb_why >> db> bt >> Tracing pid 12 tid 100026 td 0xc6755000 >> kdb_enter(c0f93c5f,c0f93c5f,c0f91e21,f08398f0,c1825c80,...) at kdb_enter+0x3d >> panic(c0f91e21,c66739a0,c0f20db8,371,c6755000,...) at panic+0x1c4 >> _mtx_lock_sleep(c68b8560,c6755000,c0f20db8,c0f20db8,371,...) at _mtx_lock_sleep+0x35e >> _mtx_lock_flags(c68b8560,0,c0f20db8,371,0,...) at _mtx_lock_flags+0xdb >> lem_start(c68ba000,0,c0fa806c,d20,2a,...) at lem_start+0x33 >> if_transmit(c68ba000,c93d9000,6,c6755000,c65da588,...) at if_transmit+0x129 >> ether_output(c68ba000,c93d9000,f0839aa4,0,0,...) at ether_output+0x5df >> arpintr(c93d9000,8,c0f50314,153,0,...) at arpintr+0x108c >> netisr_dispatch_src(7,0,c93d9000,c93d9000,c68ba000,c93d0806) at netisr_dispatch_src+0xa7 >> netisr_dispatch(7,c93d9000,c93d9000,10,3,...) at netisr_dispatch+0x20 >> ether_demux(c68ba000,c93d9000,3,0,3,...) at ether_demux+0x133 >> ether_nh_input(c93d9000,c8f012c8,644d6000,c9492d00,0,...) at ether_nh_input+0x329 >> netisr_dispatch_src(9,0,c93d9000,e2e,2,1) at netisr_dispatch_src+0xa7 >> netisr_dispatch(9,c93d9000) at netisr_dispatch+0x20 >> ether_input(c68ba000,c93d9000,c0f20db8,e2e,c11454c0,...) at ether_input+0x21 >> lem_intr(c68b6000,8,c0f8e00d,561,0,...) at lem_intr+0x567 >> intr_event_execute_handlers(c11454c0,c6626200,c0f8e00d,561,c6755000,...) at intr_event_execute_handlers+0xc5 >> ithread_loop(c6627730,f0839d08,c0f8dd64,3db,0,...) at ithread_loop+0xe2 >> fork_exit(c0a2dcb0,c6627730,f0839d08) at fork_exit+0x7c >> fork_trampoline() at fork_trampoline+0x8 >> --- trap 0, eip = 0, esp = 0xf0839d40, ebp = 0 --- >> db> show locks >> exclusive sleep mutex em0 (EM TX Lock) r = 0 (0xc68b8560) locked @ /usr/src/sys/dev/e1000/if_lem.c:1324 >> exclusive sleep mutex em0 (EM Core Lock) r = 0 (0xc68b854c) locked @ /usr/src/sys/dev/e1000/if_lem.c:1302 >> db> >> >> I need to head off to a meeting; I can poke at the machine a bit more >> in a couple of hours or so. > > I get the same panic and backtrace here, while running as a VMware > guest. At least, as soon something actually happens with the network. > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"