Re: [PATCH, RFC] panic-note: Annotation from user space for panics

David VomLehn
2009-11-18T00:06:03Z

On Tue, Nov 17, 2009 at 10:45:43AM -0500, Eric W. Biederman wrote:
...
> Why not use the kdump hook? If you handle a kernel panic that way
> you get enhanced reliability and full user space support. All in a hook
> that is already present and already works.

I'm a big fan of avoiding reinvention of the wheel--if I can use something
already present, I will. However, I'm not clear about how much of the problem
I'm addressing will be solved by using a kdump hook. If I understand
correctly, you'd still need a pseudo-file somewhere to actually get the data
from user space to kernel space. *Then* you could use a kdump hook to
transfer the data to flash or some memory area that will be retained across
boots. Is this the approach to which you were referring? If so, I have a
couple more questions:

1. In what ways would this be better than, say, a panic_notifier?
2. Where would you suggest tying in? (Particularly since not all architectures
currently support kdump)

> Eric

David VL