Re: Availability of kdb

From: Linus Torvalds (torvalds@transmeta.com)
Date: Wed Sep 06 2000 - 16:36:48 EST


On Wed, 6 Sep 2000, Dan Hollis wrote:

> On Wed, 6 Sep 2000, Alan Cox wrote:
> > For things like driver debugging its the only way to work. Hardware simply does
> > not work like the manual says and no amount of Zen contemplation will ever
> > make you at one with a 3c905B ethernet card.
>
> This is probably the best argument for a kernel debugger.
>
> Adding debug code (printk, if/then/BUG() etc) to track down a driver bug
> sometimes changes behaviour enough to turn it into a heisenbug. In these
> cases a kernel debugger is the best way to swat it.

Ehh? And exactly _how_ would a debugger help it.

Especially as Alan quoted an example of a driver bug that didn't get fixed
for several months because the maintainer didn't have the hardware.

What would a debugger have done?

Are you _seriously_ expecting that non-programmers start using kernel
debuggers to send in good bug-reports? Grow up, get a clue, and smell the
roses. Not going to happen. Especially as a kernel debugger tends to
require a second machine, and even then you only get to break
automatically on events that would have caused a kernel oops anyway.

Otherwise you need to know a hell of a lot more, like setting breakpoints
etc.

Testing is important for device drivers. Debuggers are not.

                        Linus

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