7 ms·

Response to systemd's use of the debug flag

38 points by asimov42 12y ago

ZeroGravitas 12y ago
I wonder how this whole thing would have gone down if the original bug report had simply described the problem rather than demanded their preferred solution to what they thought the problem was. Linus and others keep acting like the bug was "systemd floods the kernel logs when I pass the debug flag" but it was actually it was "Do not parse "debug" command line ". The obvious answer to the first is " Sorry about that, the bug is fixed in master branch". The obvious answer to the second is "No, that's what it's for"
- Tobu 12y ago
  I think Linus has been pretty clear on both topics (fix A, and if you won't, fix B) and on general policy (don't break it for users or I don't want to work with you in the kernel). Yeah, the reporter could have framed it better from the start, but the developers are supposed to be adults and handle imperfect bug reports too. FWIW, I don't really consider the first issue fixed. The trigger was lost in a refactoring that can't be backported, and there are probably other ways to trigger the issue.
notfoss 12y ago
I am surprised by the hostility displayed by the systemd guys. I was expecting them to admit they were wrong, and things would be back on track. With such a reply, I wonder what effect will this have on kdbus making forays into the kernel (not that I am looking forward to it ;).
anon1385 12y ago
>Correct. I don't mind people piggy-backing on some fairly obvious generic term like "debug" per se. I don't know if the old init scripts did that, but I do know they did it for "quiet", which is basically the reverse of "debug". >What I mind is people closing bugs and not admitting mistakes. If Kay had even said "sorry, the excessive output was a bug in systemd, it's already fixed in current -git", that would have been a valid reason to close the bug. So Torvalds is saying he doesn't like dictatorial project maintainers who reply in an abrupt and abrasive manner to contributors? He is so concerned about the lack of politeness and professional discourse that he just had to raise this issue? Hilarious.
- din-9 12y ago
  >> What I mind is people closing bugs and not admitting mistakes. > So Torvalds is saying he doesn't like dictatorial project maintainers who reply in an abrupt and abrasive manner to contributors? You have quoted what he did say and made up a position that he did not.
- deleted 12y ago
  [deleted]
- azernik 12y ago
  No. He doesn't like project maintainers who reply in an abrupt and dismissive way to users with bugs. In this, Linus is very consistent and not hypocritical at all.
rdtsc 12y ago
Hmm, I was expecting "Sorry we made a mistake, we'll switch the option to systemd.debug". > At that point there is simply no other option for that, because persistent storage is not available This was about overloading an already used option by another team building a core system component -- the kernel. A debug for kernel's command line is for the kernel. > It's the option an admin can specify which tells him why the system doesnt boot, Ok so he does and now his system also doesn't boot but now it is either because of the original problem or because it gets flooded by systemd logs. And then, he goes and posts to the kernel mailing lists saying how kernel is a piece of shit. > That turns this into some kind of power game, which I am totally not interested in. also > We are putting together an OS here after all, not just a kernel, and a kernel is just one component of the OS among many, and ultimately an implementation detail. I think due to their attitude towards both testing, towards the kernel community, they shouldn't be building core system components. And did he just write that kernel is just "an implementation detail?". Maybe systemd was a mistake. Integrating and dumping socket acceptors, logging, and the whole kitchen sink into one component. So when it breaks it really breaks.
- qbrass 12y ago
  >And did he just write that kernel is just "an implementation detail?". In theory, systemd could be made to work on BSDs, Hurd, Minix, or whatever. In reality, I'd sooner expect systemd to provide it's own kernel, but you never know.
  - ZeroGravitas 12y ago
    The context for that remark is: My system isn't booting. I don't know why. I'll pass "debug" to find out. Right here, and now, the fact is that the problem could be in many places inside or outside the kernel including (but not limited to) systemd. Requiring people to understand the current low level structure of their OS just to get some extra debug reporting on a failed boot is exposing implementation details.
- deleted 12y ago
  [deleted]
Orangeair 12y ago
I have a fair amount of experience with Linux, but I'm a little lost by what's going on here. Can someone out there dumb this down a bit for an init newbie?
- lutusp 12y ago
  In a nutshell, a Linux kernel developer wants to limit the number of debugging messages he is obliged to read and act on, and Linus Torvalds thinks that's counterproductive, and Linus generally says what he thinks. In a nutshell. :)
- lawl 12y ago
  You can pass the kernel options before booting. i.e. "quiet" or "debug". The Kernel exposes these options via /proc/cmdline. systemd parses /proc/cmdline and if "debug" is set, it also raises it's log level to debug. Then systemd logs so much to the kernel log that it gets flooded and fails to boot. Edit: And story wise, systemd says yeah, we're not going to fix this or rename the debug flag for systemd to "systemd.debug" because blah. And Torvalds gets pissed.
  - Orangeair 12y ago
    So basically, systemd is catching the common keyword 'debug' from a command that being given to something else entirely, and in turn enabling its own logging, which floods the system. The command wasn't actually meant for systemd, but for the kernel. Is that correct?
    - rakoo 12y ago
      You're correct, but from a user perspective it's a totally valid thing to do. When your system (or pretty much any software) doesn't work, you want to pass some "debug" flag so that the maximum information is logged and you can parse that later. You don't want to pass one debug flag per component, you want it to be global (just like when you say "quiet", you want every component to be quiet).
    - lawl 12y ago
macrael 12y ago
Google+ really doesn't get retweeting, does it. That whole post is written by someone who isn't the one in the photos at the top. A single "originally shared" link points to the original. Retweeting was a genius move by twitter, a post by someone you don't follow appears in your timeline and it looks like any other and attribution is perfectly captured.
- rg3 12y ago
  Totally agree. As things are currently, wouldn't it be best if the story link was to the actual original post? https://plus.google.com/+LennartPoetteringTheOneAndOnly/posts/VYRaUuh1tkt https://plus.google.com/+LennartPoetteringTheOneAndOnly/post...
  - macrael 12y ago
    My guess is that the comments on this one led to it being posted here (there is discussion from Linus and others down there.)
    - deleted 12y ago
      [deleted]
    - onestone 12y ago
      Yup. And Kay Sievers has another clone of the story, with a (quite unapologetic) comment of his own: https://plus.google.com/+KaySievers/posts/3cWXzYqB6MB https://plus.google.com/+KaySievers/posts/3cWXzYqB6MB
sprash 12y ago
> A kernel is just one component of the OS among many, and ultimately an implementation detail. -- Lennard Poettering
- antocv 12y ago
  Uhm without Linux specific kernel details systemd would not exist. This as well as journalctl taking minutes to show logs after months of normal usage...systemd is out from my Arch.
  - notfoss 12y ago
    May I suggest OpenRC: http://blog.notfoss.com/posts/openrc-on-arch-linux/ http://blog.notfoss.com/posts/openrc-on-arch-linux/
    - antocv 12y ago
      Thanks, I am looking into openrc, as well as gnu dmd.
- Jach 12y ago
  God damn it, now in addition to fighting off pulseaudio and systemd from being on my Gentoo box, in a few years I'm going to have to fight off the Lennart kernel...
Gigablah 12y ago
"Here's a nice note for all the reporters who are emailing me, go suck it." "Yes it's titillating, and drives page views, but really, is that the best use of an Liberal Arts degree?" Ah, the perfect guy to represent our profession.
webreac 12y ago
to be clear (I am not english). Ratelimit means drop some logs. Lennart Poettering is commplaining because he wants the kernel to be happy with him flooding the kernel with logs. When I debug software, I do not want to lose logs and I do not want software to produce so much logs it is impossible to use.
Fasebook 12y ago
thankfully we have systemd to manage these kinds of module dependency startup problems in linux now.

38 points by asimov42 12y ago

I wonder how this whole thing would have gone down if the original bug report had simply described the problem rather than demanded their preferred solution to what they thought the problem was. Linus and others keep acting like the bug was "systemd floods the kernel logs when I pass the debug flag" but it was actually it was "Do not parse "debug" command line ". The obvious answer to the first is " Sorry about that, the bug is fixed in master branch". The obvious answer to the second is "No, that's what it's for"

Tobu 12y ago
I think Linus has been pretty clear on both topics (fix A, and if you won't, fix B) and on general policy (don't break it for users or I don't want to work with you in the kernel). Yeah, the reporter could have framed it better from the start, but the developers are supposed to be adults and handle imperfect bug reports too. FWIW, I don't really consider the first issue fixed. The trigger was lost in a refactoring that can't be backported, and there are probably other ways to trigger the issue.

notfoss 12y ago

I am surprised by the hostility displayed by the systemd guys. I was expecting them to admit they were wrong, and things would be back on track. With such a reply, I wonder what effect will this have on kdbus making forays into the kernel (not that I am looking forward to it ;).

anon1385 12y ago

>Correct. I don't mind people piggy-backing on some fairly obvious generic term like "debug" per se. I don't know if the old init scripts did that, but I do know they did it for "quiet", which is basically the reverse of "debug". >What I mind is people closing bugs and not admitting mistakes. If Kay had even said "sorry, the excessive output was a bug in systemd, it's already fixed in current -git", that would have been a valid reason to close the bug. So Torvalds is saying he doesn't like dictatorial project maintainers who reply in an abrupt and abrasive manner to contributors? He is so concerned about the lack of politeness and professional discourse that he just had to raise this issue? Hilarious.

din-9 12y ago
>> What I mind is people closing bugs and not admitting mistakes. > So Torvalds is saying he doesn't like dictatorial project maintainers who reply in an abrupt and abrasive manner to contributors? You have quoted what he did say and made up a position that he did not.
deleted 12y ago
[deleted]
azernik 12y ago
No. He doesn't like project maintainers who reply in an abrupt and dismissive way to users with bugs. In this, Linus is very consistent and not hypocritical at all.

rdtsc 12y ago

Hmm, I was expecting "Sorry we made a mistake, we'll switch the option to systemd.debug". > At that point there is simply no other option for that, because persistent storage is not available This was about overloading an already used option by another team building a core system component -- the kernel. A debug for kernel's command line is for the kernel. > It's the option an admin can specify which tells him why the system doesnt boot, Ok so he does and now his system also doesn't boot but now it is either because of the original problem or because it gets flooded by systemd logs. And then, he goes and posts to the kernel mailing lists saying how kernel is a piece of shit. > That turns this into some kind of power game, which I am totally not interested in. also > We are putting together an OS here after all, not just a kernel, and a kernel is just one component of the OS among many, and ultimately an implementation detail. I think due to their attitude towards both testing, towards the kernel community, they shouldn't be building core system components. And did he just write that kernel is just "an implementation detail?". Maybe systemd was a mistake. Integrating and dumping socket acceptors, logging, and the whole kitchen sink into one component. So when it breaks it really breaks.

qbrass 12y ago
>And did he just write that kernel is just "an implementation detail?". In theory, systemd could be made to work on BSDs, Hurd, Minix, or whatever. In reality, I'd sooner expect systemd to provide it's own kernel, but you never know.
- ZeroGravitas 12y ago
  The context for that remark is: My system isn't booting. I don't know why. I'll pass "debug" to find out. Right here, and now, the fact is that the problem could be in many places inside or outside the kernel including (but not limited to) systemd. Requiring people to understand the current low level structure of their OS just to get some extra debug reporting on a failed boot is exposing implementation details.
deleted 12y ago
[deleted]

Orangeair 12y ago

I have a fair amount of experience with Linux, but I'm a little lost by what's going on here. Can someone out there dumb this down a bit for an init newbie?

lutusp 12y ago
In a nutshell, a Linux kernel developer wants to limit the number of debugging messages he is obliged to read and act on, and Linus Torvalds thinks that's counterproductive, and Linus generally says what he thinks. In a nutshell. :)
lawl 12y ago
You can pass the kernel options before booting. i.e. "quiet" or "debug". The Kernel exposes these options via /proc/cmdline. systemd parses /proc/cmdline and if "debug" is set, it also raises it's log level to debug. Then systemd logs so much to the kernel log that it gets flooded and fails to boot. Edit: And story wise, systemd says yeah, we're not going to fix this or rename the debug flag for systemd to "systemd.debug" because blah. And Torvalds gets pissed.
- Orangeair 12y ago
  So basically, systemd is catching the common keyword 'debug' from a command that being given to something else entirely, and in turn enabling its own logging, which floods the system. The command wasn't actually meant for systemd, but for the kernel. Is that correct?
  - rakoo 12y ago
    You're correct, but from a user perspective it's a totally valid thing to do. When your system (or pretty much any software) doesn't work, you want to pass some "debug" flag so that the maximum information is logged and you can parse that later. You don't want to pass one debug flag per component, you want it to be global (just like when you say "quiet", you want every component to be quiet).
  - lawl 12y ago

macrael 12y ago

Google+ really doesn't get retweeting, does it. That whole post is written by someone who isn't the one in the photos at the top. A single "originally shared" link points to the original. Retweeting was a genius move by twitter, a post by someone you don't follow appears in your timeline and it looks like any other and attribution is perfectly captured.

rg3 12y ago
Totally agree. As things are currently, wouldn't it be best if the story link was to the actual original post? https://plus.google.com/+LennartPoetteringTheOneAndOnly/posts/VYRaUuh1tkt https://plus.google.com/+LennartPoetteringTheOneAndOnly/post...
- macrael 12y ago
  My guess is that the comments on this one led to it being posted here (there is discussion from Linus and others down there.)
  - deleted 12y ago
    [deleted]
  - onestone 12y ago
    Yup. And Kay Sievers has another clone of the story, with a (quite unapologetic) comment of his own: https://plus.google.com/+KaySievers/posts/3cWXzYqB6MB https://plus.google.com/+KaySievers/posts/3cWXzYqB6MB

sprash 12y ago

> A kernel is just one component of the OS among many, and ultimately an implementation detail. -- Lennard Poettering

antocv 12y ago
Uhm without Linux specific kernel details systemd would not exist. This as well as journalctl taking minutes to show logs after months of normal usage...systemd is out from my Arch.
- notfoss 12y ago
  May I suggest OpenRC: http://blog.notfoss.com/posts/openrc-on-arch-linux/ http://blog.notfoss.com/posts/openrc-on-arch-linux/
  - antocv 12y ago
    Thanks, I am looking into openrc, as well as gnu dmd.
Jach 12y ago
God damn it, now in addition to fighting off pulseaudio and systemd from being on my Gentoo box, in a few years I'm going to have to fight off the Lennart kernel...

Gigablah 12y ago

"Here's a nice note for all the reporters who are emailing me, go suck it." "Yes it's titillating, and drives page views, but really, is that the best use of an Liberal Arts degree?" Ah, the perfect guy to represent our profession.

webreac 12y ago

to be clear (I am not english). Ratelimit means drop some logs. Lennart Poettering is commplaining because he wants the kernel to be happy with him flooding the kernel with logs. When I debug software, I do not want to lose logs and I do not want software to produce so much logs it is impossible to use.

Fasebook 12y ago

thankfully we have systemd to manage these kinds of module dependency startup problems in linux now.