Filed this as https://bugs.freedesktop.org/show_bug.cgi?id=76899
Would be great to have someone look at it. Having systemd crash due to something simple as a dangling symlink is pretty bad imho. 2014-03-27 5:18 GMT+01:00 Michael Biebl <mbi...@gmail.com>: > There is an interesting bug which can be used to crash systemd via a > dangling symlink. For details please see [0]. > > To trigger the bug, you need a socket activated service. I'm using > cups in this case. > > The steps to reproduce are > a/ Make sure cups.socket is properly configured and in state active > (listening) > b/ Make sure cups.service is *not* running > c/ Create /etc/systemd/system/cups.socket.conf.d/ and then a dangling > symlink like this ln -s /nonexistent > /etc/systemd/system/cups.socket.conf.d/foo.conf > d/ Run systemctl daemon-reload > The socket is now in this state: > Active: active (listening) > Loaded: error (Reason: No such file or directory) > e/ Now trigger a request on the cups.socket, e.g. using lpq > → systemd freezes > > The problem afaics is triggered in src/core/socket.c: > socket_enter_running(), when the incoming request causes the start of > the corresponding service unit via > r = manager_add_job(UNIT(s)->manager, JOB_START, UNIT_DEREF(s->service), > JOB_REPLACE, true, &error, NULL); > > I think after the socket configuration has been messed up and the > daemon-reload, UNIT_DEREF(s->service) does no longer point to a valid > unit, and so the assert in manager_add_job() kicks in. > > I tested this with 204 and 208, and both versions are affected. > > Any suggestions how to fix this? > > A few remarks > 1/ A dangling drop-in snippet should imho *not* cause the unit Load state to > be > Loaded: error (Reason: No such file or directory) > 2/ If a socket is in such a state, we probably shouldn't process > incoming requests and try to start the service > 3/ Should we stop the socket if the Load state is "error" > > Michael > > [0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=742322#58 > > -- > Why is it that all of the instruments seeking intelligent life in the > universe are pointed away from Earth? -- Why is it that all of the instruments seeking intelligent life in the universe are pointed away from Earth? _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
