Date: Thu, 13 Mar 2014 11:17:08 +0100 From: Attilio Rao <attilio@freebsd.org> To: Xin LI <d@delphij.net> Cc: FreeBSD Current <freebsd-current@freebsd.org>, Alexander Motin <mav@ixsystems.com> Subject: Re: processes stuck in vmo_de state Message-ID: <CAJ-FndBU5c5ZVn1zUdoS4XJnHWRhp4G2RHbKbXMTdSkQmsWebA@mail.gmail.com> In-Reply-To: <532177E0.5010905@delphij.net> References: <531EBFDC.3010608@delphij.net> <532177E0.5010905@delphij.net>
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On Thu, Mar 13, 2014 at 10:18 AM, Xin Li <delphij@delphij.net> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 > > Hi, > > It looks like there is a regression (or a regression that gets exposed > by some new feature) that is related to time-keeping or timecounter, > although I'm not yet familiar with the related code to tell if my > conclusion was right or not. > > The problem I observed is that when system boots up, it sometimes > hangs and pressing ^T on console tells me that sleep(1) is running > with 0 second out of 1 second, but the 'real' part of the output is > smaller than 1 or sometimes negative. > > For some reason the console may stop giving any output, but trapping > into debugger would unblock it sometimes. > > When sh(1) stuck in 'vmo_de' state, it would never recover from that > and a hard reset is necessary. If sleeps are not being serviced 'vmo_de' "deadlocks" makes sense because it is a sleep(1) condition. What is softclock doing at the time the deadlock happens? Attilio -- Peace can only be achieved by understanding - A. Einstein
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