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Groups > linux.kernel > #1722608

Re: printk: what is going on with additional newlines?

From Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups linux.kernel
Subject Re: printk: what is going on with additional newlines?
Date 2017-08-29 18:50 +0200
Message-ID <ujRS9-50m-9@gated-at.bofh.it> (permalink)
References <ueAff-3Y4-3@gated-at.bofh.it> <ujods-3Ju-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Mon, Aug 28, 2017 at 2:05 AM, Pavel Machek <pavel@ucw.cz> wrote:
> Hi!
>
> In 4.13-rc, printk("foo"); printk("bar"); seems to produce
> foo\nbar. That's... quite surprising/unwelcome. What is going on
> there? Are timestamps responsible?

No.

It's actively trying to treach you not to do shit.

If you want to continue a line, you NEED to use KERN_CONT.

That has always been true. It hasn't always been enforced, though.

If you do two printk's and the second one doesn't say "I'm a
continuation", the printk logic assumes you're just confused and
wanted two lines.

And no, we are *NOT* adding code to printk to help people avoid this.
Quite the reverse.

Stop doing continuations at all please. But if you do, you'd better
use KERN_CONT. And if you don't, and you get multiple lines, it's your
own damn fault.

                 Linus

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Thread

printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-28 11:10 +0200
  Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 12:30 +0200
    Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 14:30 +0200
      Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 14:40 +0200
      Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-28 14:50 +0200
        Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-29 15:50 +0200
          Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 18:40 +0200
          Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:10 +0200
            Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:20 +0200
              Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-08-29 22:50 +0200
                Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 23:00 +0200
                Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-09-02 08:20 +0200
                Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-02 19:10 +0200
              Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-08-30 02:00 +0200
                Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-30 02:00 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:10 +0200
                Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-08-30 03:20 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:50 +0200
                Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 04:00 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 04:30 +0200
                Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 04:40 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 04:50 +0200
                Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 05:00 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 07:40 +0200
                Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-08 12:20 +0200
                Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-05 11:50 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-05 12:10 +0200
                Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-05 14:30 +0200
                Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-09-05 14:40 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-09-05 16:30 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-05 15:50 +0200
                Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-06 10:00 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-09-01 15:30 +0200
                Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 19:40 +0200
                Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-01 22:30 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 07:30 +0200
                Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-04 07:50 +0200
                Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-09-05 17:00 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-06 04:20 +0200
                Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-06 04:40 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 06:40 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 07:30 +0200
            Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-08-29 19:40 +0200
              Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 20:00 +0200
                Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 20:10 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:10 +0200
                Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:00 +0200
  Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 18:50 +0200
    Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:20 +0200
      Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:30 +0200
        Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:40 +0200
          Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:40 +0200
            Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:50 +0200
    Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-29 22:30 +0200
      Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-01 03:50 +0200
        Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 04:10 +0200
          Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-01 09:00 +0200
            Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 09:30 +0200
        Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-01 09:30 +0200
          Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-09-01 13:20 +0200

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