4 ms·

Wait. To run an unscheduled fsck of your root fs (and only your root fs), you have to remove the execute bit from a systemd component, kill that component, the

Wait. To run an unscheduled fsck of your root fs (and only your root fs), you have to remove the execute bit from a systemd component, kill that component, then remember to reset the bit after you're done? That's nuts.

morganvachon 11y ago
That kind of thing is why I stick with Slackware and OpenBSD for my production systems. systemd has some great ideas, but it has some down right silliness as well, and I personally don't feel it's stable enough for daily use yet.
rdtsc 11y ago
(Just to make sure everyone gets it) It will prevent it from running again. So it is basically a big FU! to systemd. "So you you think you gonna restart yourself? Oh, no you won't"
pdkl95 11y ago
That's nothing - systemd panics (pid1 crash) if you restart dbus, which requires either the Magic SysRq or the reset button.. https://forums.gentoo.org/viewtopic-p-7811550.html#7811550 https://forums.gentoo.org/viewtopic-p-7811550.html#7811550 Pottering was apparently told about this in 2013, when he simply declared it expected behavior because dbus was "rock solid". http://lists.freedesktop.org/archives/systemd-devel/2013-January/008456.html http://lists.freedesktop.org/archives/systemd-devel/2013-Jan... Incidentally, this might be the original reason for kdbus - it's harder to restart the daemon after it becomes a kernel module.
- simoncion 11y ago
  > Incidentally, this might be the original reason for kdbus... Yeah, especially given that its stated reason (Moving into the kernel gives us a 2x speedup over userspace dbus! Dbus is slow and we NEEED the speedup!) is mooted by the 10x speedup that cleaning up the userspace dbus libraries has achieved. [0] Having said that, in the systemd-devel post Poettering says that they're working on... > ...improving this in two ways: even if it still brings down the system, at least allow logind to handle this case nicely, so that you get a sane getty. [The other way is to push dbus into the kernel.] Systemd is a sprawling project, so I could see why it has taken more than two-and-a-half years to fix a local DOS caused by the perfectly normal method of responding to a DBUS upgrade. ;) [0] Fun fact: Those cleaned up libraries were supposed to be released after kdbus was merged into the kernel in 4.1. The Systemd Cabal was so disappointed that they had to ship the performant userspace dbus libs before the dbus daemon got pushed into kernelspace.
  - tmd83 11y ago
    I am by no means knowledgable in the relevant domain yet this is scary at so many levels. The team that is taking charge of so many critical infrastructure not doing a minimal level of fact finding before pushing for a new kernel module for RPC is a bit obscene. I may have read things that are biased but I have a feeling it is a useful project and it does a lot of thing elegantly or right. But the project acts like it is the center of the universe and all should act to meet its needs. I have seen such project/modules at work, they usually makes everyone happy to start with and down the road when they finally get stuck and I am forced to consult we are already long way down the slope.
    - intelfx 11y ago
      Goddamn, guys, stop repeating the same absurd. kdbus is NOT ONLY about performance. It's about the lifetimes, the availiability in the early userspace, the new marshalling format, the new user bus concept, and so on, and so forth. It's about separating the transport (in the kernel) and the policy (in the userspace). Most of these points can be achieved without putting the transport in the kernel, but some can not.
      - tmd83 11y ago
        Yeah right. No wonder I see people adding all sorts of adjective to the systemd proponent. I don't usually go hunting for sources and I only had Linus's comment about kdbus and performance. So I went to look for pottering's own word and here is a verbatime quote from the abstract of his presentation on kdbus D-Bus is a powerful design. However, being mostly a userspace solution its latency and throughput are not ideal. A full transaction consisting of method call and method reply requires 10 (!) copy operations for the messages passed. It is only useful for transfer of control messages, and not capable of streaming larger amounts of data. So yeah he tried to sell performance as the big thing for his version of dbus IPC. I'm guessing he (and group) spent more time with dbus than linus and failed to find the actual cause of the performance issue or tried to hide it give more credence to kdbus. In both cases it makes it that much harder to trust their reasoning and conclusions. I never said kdbus is ONLY about performance. But from what I'm reading they are not performance people but they think they are. The most dangerous people are those who don't know their own limitation or weakness. And your comment simply emphasise the practice of listening whats being said. So yeah given that I don't know dbus or ipc I have to trust your logic and you only make it hard to do so.

morganvachon 11y ago

That kind of thing is why I stick with Slackware and OpenBSD for my production systems. systemd has some great ideas, but it has some down right silliness as well, and I personally don't feel it's stable enough for daily use yet.

rdtsc 11y ago

(Just to make sure everyone gets it) It will prevent it from running again. So it is basically a big FU! to systemd. "So you you think you gonna restart yourself? Oh, no you won't"

pdkl95 11y ago

That's nothing - systemd panics (pid1 crash) if you restart dbus, which requires either the Magic SysRq or the reset button.. https://forums.gentoo.org/viewtopic-p-7811550.html#7811550 https://forums.gentoo.org/viewtopic-p-7811550.html#7811550 Pottering was apparently told about this in 2013, when he simply declared it expected behavior because dbus was "rock solid". http://lists.freedesktop.org/archives/systemd-devel/2013-January/008456.html http://lists.freedesktop.org/archives/systemd-devel/2013-Jan... Incidentally, this might be the original reason for kdbus - it's harder to restart the daemon after it becomes a kernel module.

simoncion 11y ago
> Incidentally, this might be the original reason for kdbus... Yeah, especially given that its stated reason (Moving into the kernel gives us a 2x speedup over userspace dbus! Dbus is slow and we NEEED the speedup!) is mooted by the 10x speedup that cleaning up the userspace dbus libraries has achieved. [0] Having said that, in the systemd-devel post Poettering says that they're working on... > ...improving this in two ways: even if it still brings down the system, at least allow logind to handle this case nicely, so that you get a sane getty. [The other way is to push dbus into the kernel.] Systemd is a sprawling project, so I could see why it has taken more than two-and-a-half years to fix a local DOS caused by the perfectly normal method of responding to a DBUS upgrade. ;) [0] Fun fact: Those cleaned up libraries were supposed to be released after kdbus was merged into the kernel in 4.1. The Systemd Cabal was so disappointed that they had to ship the performant userspace dbus libs before the dbus daemon got pushed into kernelspace.
- tmd83 11y ago
  I am by no means knowledgable in the relevant domain yet this is scary at so many levels. The team that is taking charge of so many critical infrastructure not doing a minimal level of fact finding before pushing for a new kernel module for RPC is a bit obscene. I may have read things that are biased but I have a feeling it is a useful project and it does a lot of thing elegantly or right. But the project acts like it is the center of the universe and all should act to meet its needs. I have seen such project/modules at work, they usually makes everyone happy to start with and down the road when they finally get stuck and I am forced to consult we are already long way down the slope.
  - intelfx 11y ago
    Goddamn, guys, stop repeating the same absurd. kdbus is NOT ONLY about performance. It's about the lifetimes, the availiability in the early userspace, the new marshalling format, the new user bus concept, and so on, and so forth. It's about separating the transport (in the kernel) and the policy (in the userspace). Most of these points can be achieved without putting the transport in the kernel, but some can not.
    - tmd83 11y ago
      Yeah right. No wonder I see people adding all sorts of adjective to the systemd proponent. I don't usually go hunting for sources and I only had Linus's comment about kdbus and performance. So I went to look for pottering's own word and here is a verbatime quote from the abstract of his presentation on kdbus D-Bus is a powerful design. However, being mostly a userspace solution its latency and throughput are not ideal. A full transaction consisting of method call and method reply requires 10 (!) copy operations for the messages passed. It is only useful for transfer of control messages, and not capable of streaming larger amounts of data. So yeah he tried to sell performance as the big thing for his version of dbus IPC. I'm guessing he (and group) spent more time with dbus than linus and failed to find the actual cause of the performance issue or tried to hide it give more credence to kdbus. In both cases it makes it that much harder to trust their reasoning and conclusions. I never said kdbus is ONLY about performance. But from what I'm reading they are not performance people but they think they are. The most dangerous people are those who don't know their own limitation or weakness. And your comment simply emphasise the practice of listening whats being said. So yeah given that I don't know dbus or ipc I have to trust your logic and you only make it hard to do so.