4 ms·

It's weird to me that text encoding is put in the domain of the kernel. But I guess it's the way it needs to be until the world moves to microkernels.

layer8 4y ago
This seems to be about the system console built into the kernel.
- yakubin 4y ago
  Yeah, I got that part. I've just assumed that would be handled by a server process in a microkernel architecture. But I've just checked seL4 and it has in-kernel support for the console as well. That's not what I expected.
  - MisterTea 4y ago
    The system terminal has to be in-kernel otherwise you would not see kernel prints during boot, before any fs (and servers launched from it) is mounted.
hinkley 4y ago
Even with a microkernel, there's a lot of power in having a text console even when half the system is not functioning. If this code exists in a separate process, a lot of the handling bugs still need to be fixed to make the OS usable.
- snvzz 4y ago
  Serial port is trivial.
  - Lt_Riza_Hawkeye 4y ago
    okay... and something needs to be able to decode the text sent to it over the serial port. All the bugs pointed out in the article also happen if you use the serial port console
    - comex 4y ago
      Yes, and that “something” can be an app like gnome-terminal running on a full-fat text rendering library and GUI framework… on a completely different computer. That software could hypothetically have the same bug, but probably not, and at any rate it‘s not taking up space in the core of a microkernel.
  - matja 4y ago
    The 120k+ lines of code in drivers/tty/serial in Linux suggests that maybe it's not _that_ trivial.
jamal-kumar 4y ago
Yeah, what's even weirder is when it's so integral to the kernel that it can lead to crashes. I've seen more than one case now where someone just fuzzing around on text engines ends up taking down an entire system, at least a couple on mac osx and ios alone. Dangerous stuff. [1] [2] Linux might not be the most performant in the text engine game but at least it runs in userland. [1] https://arstechnica.com/gadgets/2013/08/rendering-bug-crashes-os-x-and-ios-apps-with-string-of-arabic-characters/ https://arstechnica.com/gadgets/2013/08/rendering-bug-crashe... [2] https://www.engadget.com/unusual-buggy-character-string-apple-devices-crash-120521234.html https://www.engadget.com/unusual-buggy-character-string-appl...
phoehne 4y ago
I've been waiting for a "true" microkernel OS since 1980s.
- lproven 4y ago
  QNX and Minix 3 don't count?

layer8 4y ago

This seems to be about the system console built into the kernel.

yakubin 4y ago
Yeah, I got that part. I've just assumed that would be handled by a server process in a microkernel architecture. But I've just checked seL4 and it has in-kernel support for the console as well. That's not what I expected.
- MisterTea 4y ago
  The system terminal has to be in-kernel otherwise you would not see kernel prints during boot, before any fs (and servers launched from it) is mounted.

hinkley 4y ago

Even with a microkernel, there's a lot of power in having a text console even when half the system is not functioning. If this code exists in a separate process, a lot of the handling bugs still need to be fixed to make the OS usable.

snvzz 4y ago
Serial port is trivial.
- Lt_Riza_Hawkeye 4y ago
  okay... and something needs to be able to decode the text sent to it over the serial port. All the bugs pointed out in the article also happen if you use the serial port console
  - comex 4y ago
    Yes, and that “something” can be an app like gnome-terminal running on a full-fat text rendering library and GUI framework… on a completely different computer. That software could hypothetically have the same bug, but probably not, and at any rate it‘s not taking up space in the core of a microkernel.
- matja 4y ago
  The 120k+ lines of code in drivers/tty/serial in Linux suggests that maybe it's not _that_ trivial.

jamal-kumar 4y ago

Yeah, what's even weirder is when it's so integral to the kernel that it can lead to crashes. I've seen more than one case now where someone just fuzzing around on text engines ends up taking down an entire system, at least a couple on mac osx and ios alone. Dangerous stuff. [1] [2] Linux might not be the most performant in the text engine game but at least it runs in userland. [1] https://arstechnica.com/gadgets/2013/08/rendering-bug-crashes-os-x-and-ios-apps-with-string-of-arabic-characters/ https://arstechnica.com/gadgets/2013/08/rendering-bug-crashe... [2] https://www.engadget.com/unusual-buggy-character-string-apple-devices-crash-120521234.html https://www.engadget.com/unusual-buggy-character-string-appl...

phoehne 4y ago

I've been waiting for a "true" microkernel OS since 1980s.

lproven 4y ago
QNX and Minix 3 don't count?