Date: Mon, 9 Feb 2015 16:38:00 +0200 From: Alexander Yerenkow <yerenkow@gmail.com> To: Andre Albsmeier <andre@fbsd.ata.myota.org> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: [unionfs] deadlocking a 9-STABLE machine with two unionfs mounts onto the same mountpoint Message-ID: <CAPJF9wkSvQXMdhatdK8xQq9SXCxDdCC69ZOCpqv6aDSBsSgp4w@mail.gmail.com> In-Reply-To: <20150209142242.GA8734@schlappy> References: <20150209142242.GA8734@schlappy>
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2015-02-09 16:22 GMT+02:00 Andre Albsmeier <andre@fbsd.ata.myota.org>: > Retrying here as -fs didn't show up any results... > > ----- Forwarded message ----- > > I can reliably deadlock a 9.3-STABLE by the following procedure: > > Let's assume that /tmp is a standard swap-backed file system > already. First let's set up what we need: > > mkdir /tmp/1 /tmp/2 > mount -v -t unionfs /tmp/1 /usr/local > mount -v -t unionfs /tmp/2 /usr/local > Few years ago case was even simplier mkdir /tmp/1 mount -v -t unionfs /tmp/1 /usr/local #yep, just twice mount mount -v -t unionfs /tmp/1 /usr/local ls /tmp/1 #and the shell hangs. > > No let's lock the system: > > mkdir /tmp/2/bla > while :; do > echo go > tar -cC /usr/src/etc -f - . | tar -xpC /tmp/2/bla -f - > done > > It survives about 3 or 4 rounds, sometimes more, sometimes > only 2. It is important to use tar to copy the stuff. If > we replace the tar line by e.g. > > cp -pR /usr/src/etc/* /tmp/2/bla > > things are all well. > > The system doesn't lock up entirely, you can move the mouse > and ping it but no fs access is possible anymore. One can > switch to the console and enter the debugger but a reboot > with ctrl-alt-del doesn't work... > > The interesting part is that all this worked pretty well on > 9-STABLE until approx. 2 months ago. But nothing had been > committed to unionfs for a long time so I really have no > idea what's going on. > > It also reminds us of > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=161511 > > but this stuff had been merged to 9-STABLE already... > > Anything I can do to get this fixed? > > ----- End forwarded message ----- > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > -- Regards, Alexander Yerenkow
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