From owner-freebsd-stable@FreeBSD.ORG Sun Jul 22 17:26:01 2007 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CD85A16A419 for ; Sun, 22 Jul 2007 17:26:01 +0000 (UTC) (envelope-from nox@saturn.kn-bremen.de) Received: from gwyn.kn-bremen.de (gwyn.kn-bremen.de [212.63.36.242]) by mx1.freebsd.org (Postfix) with ESMTP id 9099813C442 for ; Sun, 22 Jul 2007 17:26:01 +0000 (UTC) (envelope-from nox@saturn.kn-bremen.de) Received: by gwyn.kn-bremen.de (Postfix, from userid 10) id B63E11CBDF8; Sun, 22 Jul 2007 18:55:18 +0200 (CEST) Received: from saturn.kn-bremen.de (nox@localhost [127.0.0.1]) by saturn.kn-bremen.de (8.13.8/8.13.6) with ESMTP id l6MGrWm4003869; Sun, 22 Jul 2007 18:53:32 +0200 (CEST) (envelope-from nox@saturn.kn-bremen.de) Received: (from nox@localhost) by saturn.kn-bremen.de (8.13.8/8.13.6/Submit) id l6MGrWMu003868; Sun, 22 Jul 2007 18:53:32 +0200 (CEST) (envelope-from nox) Date: Sun, 22 Jul 2007 18:53:32 +0200 (CEST) From: Juergen Lock Message-Id: <200707221653.l6MGrWMu003868@saturn.kn-bremen.de> To: mime@traveller.cz X-Newsgroups: local.list.freebsd.stable In-Reply-To: <1184792674.1670.7.camel@genius.i.cz> Organization: home Cc: freebsd-stable@freebsd.org Subject: Re: Panic with umass (with USB tape and Amanda) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 22 Jul 2007 17:26:01 -0000 In article <1184792674.1670.7.camel@genius.i.cz> you write: >Hello everybody, Hi! > >I have just had a panic on 6.2 amd64 box with ehci connected USB DDS4 >tape drive while it was for the first time being accessed with Amanda. I >have previously successfully tested it with tar. > >I have a kernel crash dump with the following information: > >panic: trying to sleep while sleeping is prohibited >cpuid = 0 >KDB: stack backtrace: >panic() at panic+0x250 >sleepq_add() at sleepq_add+0x225 >msleep() at msleep+0x132 >bwait() at bwait+0x55 >swap_pager_putpages() at swap_pager_putpages+0x45c >vm_pageout_flush() at vm_pageout_flush+0x13b >vm_contig_launder_page() at vm_contig_launder_page+0xdc >vm_page_alloc_contig() at vm_page_alloc_contig+0x321 >contigmalloc() at contigmalloc+0x5f7 >bus_dmamem_alloc() at bus_dmamem_alloc+0x80 >usb_block_allocmem() at usb_block_allocmem+0x118 >... This looks like the known problem of bus_dmamem_alloc sleeping when it shouldn't (its being called with BUS_DMA_NOWAIT), which has hit me with usb before. Workarounds: 1. add more RAM (this seems to be triggered by page shortage/fragmentation) 2. reboot before you use the device 3. try the HPS usb stack, it may have worked around this issue: http://www.turbocat.net/~hselasky/usb4bsd/ (I hope this is still the right url, I haven't used the stack in a while.) HTH, Juergen