Date: Wed, 6 May 2020 14:04:21 -0500 From: Kyle Evans <kevans@freebsd.org> Cc: Kurt Jaeger <pi@freebsd.org>, jail@freebsd.org Subject: Re: Should killed process deref a jail? Message-ID: <CACNAnaHJhpgvBdRS%2BSEweHCYmByonu0gvCS0W=e__YG5x2XNGg@mail.gmail.com> In-Reply-To: <CACNAnaFvyhD-CXozcntui%2Bgd4gvMTgzHUnVbTYCMJfaWHNJM5g@mail.gmail.com> References: <CACNAnaGssAKJ1-LhfQ1yszkOYkGw0iDsFgxmcuEZmTf9M-hyTg@mail.gmail.com> <20200506184923.GT39563@home.opsec.eu> <CACNAnaFvyhD-CXozcntui%2Bgd4gvMTgzHUnVbTYCMJfaWHNJM5g@mail.gmail.com>
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On Wed, May 6, 2020 at 1:55 PM Kyle Evans <kevans@freebsd.org> wrote: > > On Wed, May 6, 2020 at 1:49 PM Kurt Jaeger <pi@freebsd.org> wrote: > > > > Hi! > > > > > In doing some testing of qemu-user-static recently, I noticed that > > > killing the last process in a non-persist jail doesn't kill off the > > > jail: > > > > > > root@viper:/usr/src# jail -c path=/ command=yes > > > ## ^C out > > > > > > root@viper:/usr/src# jls > > > JID IP Address Hostname Path > > > 181 / > > > > > > root@viper:/usr/src# ps fxJ 181 > > > PID TT STAT TIME COMMAND > > > > > > As a result, I ended up with 82 jails pointed at my armv7 sysroot and > > > much surprise when I checked out `jls`. This vaguely smells like a > > > bug, is this something that should be fixed? > > > > Depends. If the last process held some socket and the socket > > is still in the state LINGER. > > > > See > > > > https://deepix.github.io/2016/10/21/tcprst.html > > > > for more details, after the heading 'What is SO_LINGER?' > > > > You can probably see those sockets with > > > > That'd make sense, but in this case it's actually reproducible with > yes(1), which doesn't open up any sockets or actually use any external > resources other than write()ing to stdout. This turns out to be PEBCAK, as jail(8) will always set persist if there's a command to be run. Sorry for the noise...
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