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posted by CoolHand on Wednesday October 05 2016, @12:46AM   Printer-friendly
from the love-for-lennart dept.

Security researcher and MateSSL founder, Andrew Ayer has uncovered a bug which will either crash or make systemd unstable (depending on who you talk to) on pretty much every linux distro. David Strauss posted a highly critical response to Ayer. In true pedantic nerd-fight fashion there is a bit of back and forth between them over the "true" severity of the issue and what not.

Nerd fights aside, how you feel about this bug, will probably largely depend on how you feel about systemd in general.

The following command, when run as any user, will crash systemd:

NOTIFY_SOCKET=/run/systemd/notify systemd-notify ""

After running this command, PID 1 is hung in the pause system call. You can no longer start and stop daemons. inetd-style services no longer accept connections. You cannot cleanly reboot the system. The system feels generally unstable (e.g. ssh and su hang for 30 seconds since systemd is now integrated with the login system). All of this can be caused by a command that's short enough to fit in a Tweet.

Edit (2016-09-28 21:34): Some people can only reproduce if they wrap the command in a while true loop. Yay non-determinism!


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  • (Score: 5, Insightful) by jmorris on Wednesday October 05 2016, @01:27AM

    by jmorris (4844) on Wednesday October 05 2016, @01:27AM (#410433)

    It isn't that this bug won't be swiftly squashed. It will be, and the distros will push updates quickly. The problem is that systemd, like all of the Red Hat / Pottering OS "Alien Tech" is built around the same defective ideas that have meant Windows NT / XP / 7 / 8 / 10 have been and probably always be roach motels. Big monoliths are inherently unstable because they are too big to know.

    When nobody knows all of the details of how a system works they have three choices.

    1. Muddle through as best as one can because ya got a job to do. a few years accretion of the cruft that sort of thing brings on is why Windows can never be fixed, only tossed and rewritten. In exactly the same way as the open source world tried for a bit to whip the original source dump of Netscape into shape only to mostly toss it and rewrite something simpler and without the years of accumulated cruft. Systemd is on this course.

    2. Admit defeat and don't touch it. Meaning you use a distro that doesn't use any of the "Alien Tech" and get on with a happier life.

    3. Spend large amounts of time and effort to understand it... if you are capable and the docs exist. This cuts the userbase down to nothing so never actually happens in the real world. People have better things to do with their life, except for the elect few being paid by RedHat to develop this crap. Or you can buy a service contract... and pay Red Hat to know how it works. Which is what they are trying to achieve. But it will probably fail, Microsoft too tried this tactic and very quickly found they couldn't understand it either.

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  • (Score: 5, Interesting) by TheGratefulNet on Wednesday October 05 2016, @01:38AM

    by TheGratefulNet (659) on Wednesday October 05 2016, @01:38AM (#410437)

    history will likely show that the intro of systemd was the downfall of linux.

    I hope we recover and undo systemd at some future date. why it was pushed out to SO many distros (redhat, yes, I understand; debian based ones, though, I have no idea why that ended up being voted in) - its just a damned shame that its not limited to ONE 'test' distro. let the testers have their fun, but on PRODUCTION, wow, just wow.

    it really does show that the 'kids are in control' and they seem to have such attitudes that they KNOW better than us greyhairs. sigh....

    well, there is the BSD distros. I guess we can think about switching over. I was once a big freebsd guy, myself, back when linux was still going stable/unstable back and forth. then, a few years ago, it got stable enough that I dumped all my bsd systems. at this point, I may have to think about going back; but linux has taken over the embedded world and no one (that I know of) runs bsd on their embedded hardware anymore. all the jobs I've seen and have interviewed for have been linux.

    --
    "It is now safe to switch off your computer."
    • (Score: -1, Flamebait) by Anonymous Coward on Wednesday October 05 2016, @01:48AM

      by Anonymous Coward on Wednesday October 05 2016, @01:48AM (#410442)

      history will likely show that the intro of systemd was the downfall of linux

      And you Linux scum will deserve it, because asshole Linux followers were the downfall of GNU. It is fitting that systemd will be the downfall of you. Bye bye fuckers.

    • (Score: 1, Informative) by Anonymous Coward on Wednesday October 05 2016, @12:01PM

      by Anonymous Coward on Wednesday October 05 2016, @12:01PM (#410548)

      The standard linux is still free of it. http://slackware.com/ [slackware.com]

      • (Score: 0) by Anonymous Coward on Sunday October 09 2016, @01:27PM

        by Anonymous Coward on Sunday October 09 2016, @01:27PM (#412049)

        For now.

        One may wonder if they will adopt systemd or drop every big DE from their repository when time comes...

    • (Score: 2) by VLM on Wednesday October 05 2016, @12:52PM

      by VLM (445) Subscriber Badge on Wednesday October 05 2016, @12:52PM (#410561)

      linux has taken over the embedded world

      How long will that last in a world of Gnome boot-loading windows architecture?

      Look smaller. I have an olimex dev board on my desk at home to play with, its just an overgrown pic32, and in my infinite spare time I'm going to retro-BSD it. The point being that embedded as in "I velcro'd mah tablet onto mah refrigerator" is going all linux-y but coming up from the bottom the low performance PIC in your next toaster might very well be running *BSD.

      I mean if you want a unix like internet grade OS, thats not linux anymore, but the good news is even lower end microcontrollers are getting powerful enough to run real unix, and a real unix is probably a good OS for "internet of crappy things" and all those buzzwords. You want something that works in a toaster, not something that finally solves automounting floppy disks on gnome desktop (in 2016) at enormous reliability and security cost.

    • (Score: 0) by Anonymous Coward on Wednesday October 05 2016, @02:04PM

      by Anonymous Coward on Wednesday October 05 2016, @02:04PM (#410592)

      Try antiX Linux? Proudly (almost!! damn thing is like aids to flush out) systemd free!

    • (Score: 2) by Kromagv0 on Wednesday October 05 2016, @02:31PM

      by Kromagv0 (1825) on Wednesday October 05 2016, @02:31PM (#410613) Homepage

      Well there is always Slackware. if they go to systemd you know it will be here for the long haul.

      --
      T-Shirts and bumper stickers [zazzle.com] to offend someone
    • (Score: 0) by Anonymous Coward on Wednesday October 05 2016, @03:17PM

      by Anonymous Coward on Wednesday October 05 2016, @03:17PM (#410637)

      iOS is based on FreeBSD like MacOS is, so at least one embedded device running *BSD

    • (Score: 2) by hopp on Wednesday October 05 2016, @07:06PM

      by hopp (2833) on Wednesday October 05 2016, @07:06PM (#410771)

      It was the inclusion of systemd which made me take another look at FreeBSD for our systems. We left FreeBSD when the whole 4-5 upgrade debacle happened and happily returned to FreeBSD when systemd became the standard. bhyve is actually a pretty nice way to layer vm over the zfs and upgrades and auditing are a breeze.

      We're a tiny shop so we matter to no one and we may go back to linux some day but for now BSD is our best option.

  • (Score: -1, Disagree) by Anonymous Coward on Wednesday October 05 2016, @01:41AM

    by Anonymous Coward on Wednesday October 05 2016, @01:41AM (#410439)

    Windows NT / XP / 7 / 8 / 10 have been and probably always be roach motels. Big monoliths are inherently unstable because they are too big to know.

    Oh dear holy shit, the blatant ignorance burns the eyes. You know the Linux kernel is monolithic, right? Are you aware of the debate between Torvalds and Tanenbaum regarding microkernel design? You know NT is a microkernel, right?

    You know what, fuck you. Fuck you and fuck every Linux user who is as willfully fucking ignorant and biased as you. Go fuck yourselves, all of you. You're all complete shit. Burn in hell.

    • (Score: 3, Informative) by butthurt on Wednesday October 05 2016, @02:03AM

      by butthurt (6141) on Wednesday October 05 2016, @02:03AM (#410456) Journal

      > You know NT is a microkernel, right?

      That was abandoned with Windows NT 4.0:

      The major architectural change in this version of Windows NT is the move of the Window Manager, Graphics Device Interface (GDI), and higher-level device drivers from the Win32 environment subsystem into the Windows NT Executive as an executive service.
      [...]
      The most significant aspect of this change is that graphics services, which used to run in user mode like applications, now run in kernel mode like most of the operating system. The idea behind kernel mode and its alternative, user mode, is to separate applications from the operating system. Applications run in user mode; operating systems run in kernel mode.

      Kernel mode is a highly privileged mode of operation where the code has direct access to all memory, including the address spaces of all user-mode processes and applications, and to hardware.

      -- https://www.microsoft.com/resources/documentation/windowsnt/4/workstation/reskit/en-us/archi.mspx [microsoft.com]

    • (Score: 2) by Dunbal on Wednesday October 05 2016, @02:32AM

      by Dunbal (3515) on Wednesday October 05 2016, @02:32AM (#410467)

      No seriously - tell us how you really feel, AC.

    • (Score: 2, Informative) by Arik on Wednesday October 05 2016, @06:19AM

      by Arik (4543) on Wednesday October 05 2016, @06:19AM (#410513) Journal
      Neither NT nor Linux are pure types. NT started with a microkernel and over time evolved into a monolithic kernel, while Linux has done the opposite.

      And that's all completely beside the point you were replying to. He wasn't talking about a monolithic kernel necessarily. He was talking about monolithic system design. Systemd has not yet had much effect on the kernel at all, but it's still a giant monolithic pile of poo no matter what kernel it runs under.
      --
      If laughter is the best medicine, who are the best doctors?