Date: Wed, 12 May 2010 16:11:54 +0200 From: Ulrich =?utf-8?B?U3DDtnJsZWlu?= <uqs@spoerlein.net> To: Attilio Rao <attilio@freebsd.org> Cc: current@freebsd.org, Peter Jeremy <peterjeremy@acm.org> Subject: Re: LOR: ufs vs bufwait Message-ID: <20100512141154.GF88504@acme.spoerlein.net> In-Reply-To: <u2h3bbf2fe11005101353k493f3ca3v7c1216e840820c67@mail.gmail.com> References: <20100508102005.GB1867@elmar.spoerlein.net> <20100510061057.GA93038@server.vk2pj.dyndns.org> <u2h3bbf2fe11005101353k493f3ca3v7c1216e840820c67@mail.gmail.com>
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On Mon, 10.05.2010 at 22:53:32 +0200, Attilio Rao wrote: > 2010/5/10 Peter Jeremy <peterjeremy@acm.org>: > > On 2010-May-08 12:20:05 +0200, Ulrich Spörlein <uqs@spoerlein.net> wrote: > >>This LOR also is not yet listed on the LOR page, so I guess it's rather > >>new. I do use SUJ. > >> > >>lock order reversal: > >> 1st 0xc48388d8 ufs (ufs) @ /usr/src/sys/kern/vfs_lookup.c:502 > >> 2nd 0xec0fe304 bufwait (bufwait) @ /usr/src/sys/ufs/ffs/ffs_softdep.c:11363 > >> 3rd 0xc49e56b8 ufs (ufs) @ /usr/src/sys/kern/vfs_subr.c:2091 > > > > I'm seeing exactly the same LOR (and subsequent deadlock) on a recent > > -current without SUJ. > > I think this LOR was reported since a long time. > The deadlock may be new and someway related to the vm_page_lock work > (if not SUJ). I was not able to reproduce this with a kernel prior to SUJ, a kernel just after SUJ went it shows this "deadlock" or infinite loop ... Now it might be that the SUJ kernel only increases the pressure so it happens during a systems uptime. It does not seem directly related to actually using SUJ on a volume, as I could reproduce it with SU only, too. I will try to get a hang not involving GELI and also re-do my tests when the volumes have neither SUJ nor SU enabled, which led to 10-20s "hangs" of the system IIRC. It seems SU/SUJ then only prolongs these hangs ad infinitum. I'll be back next week with new results here Uli
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