Re: Warning and BUG with btrfs and corrupted image

From: Pavel Machek
Date: Thu Feb 05 2009 - 04:03:36 EST



> > > CONFIG_*_DEBUG means include *debug* code there to help developers,
> > > including adding additional failure tests into the kernel. Besides,
> > > which bit of "don't turn it on unless you are an XFS developer"
> > > don't you understand?
> >
> > Yes, but DEBUG code is normally to help debugging, not to crash
> > kernels.
>
> Crashing the kernel at exactly the point a problem is detected
> is often the simplest way of debugging the problem.
>
> e.g. CONFIG_VM_DEBUG=y turns on VM_BUG_ON() which crashes the kernel
> whenever it detects something wrong. Do I turn it on? Yes. Do i

That's different. User is not supposed to be able to trigger
VM_BUG_ON().

> complain about it when I hit a VM_BUG_ON()? No, I report the
> bug and move on. If you turn on a DEBUG option, then you are
> asking the system to behave in a way useful to a developer,
> not an end user. That includes panicing when something wrong
> is detected.

Imagine vm going panic() on mkdir("/lost+found")...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/