On Tue, Sep 28, 2010 at 03:04:11PM -0400, John Baldwin wrote:
> > I am bigger fan of textdumps than minidumps, because in my opinion
> > textdumps provide quite a lot of useful info. I'm working with FreeBSD
> > kernel for years now and almost entirely avoided gdb for kernel
> > debugging. DDB and printf(9) are in 99% enough for me (maybe I'm too
> > traditional, but that's the fact). I'm not saying that textdumps are
> > enough in 99%, though.
> Have you looked at a /var/crash/core.txt.X file yet? If not, you should, as
> it is very similar to a text dump. In fact, it will contain the contents of
> any ddb trace buffer in addition to a stack trace from kgdb, process listing
> from ps, etc.
> > Another important thing in my opinion is privacy of user's data. Once
> > the data hit the disk it can stay there forever. This is why I use
> > encrypted swap everywhere. I'd never send kernel minidump from my
> > laptop or from any of my servers to anyone, but I'd be happy to send
> > textdump.
> > I find textdumps a great solution that's in the middle between
> > protecting user's privacy and providing a lot of useful info and I'd
> > much prefer to turn on textdumps by default and eventually extend what
> > we dump, than to make minidumps the default.
> I'm suggesting they provide us the core.txt.X file, not the full minidump.
> A developer could then ask them to run specific commands from a subsequent
> kgdb session to obtain more details.
But you still will have your kernel memory dumped to disk. This is
probably not a problem for most of the users, though.
> > You can always ask user to add this one-line to rc.conf to turn
> > minidump on and provide you the info that was missing in textdump.
> This only works for easily reproducible bugs, and in that case they can turn
> on dumps later without a need for it to be automatic at all.
And I'm arguing that those are very rare situations where there is a
bug, which is hard to reproduce and where textdump won't be of any help.
I'm aware that those are not strong arguments, but just worth taking
into account, IMHO.
Pawel Jakub Dawidek http://www.wheelsystems.com
FreeBSD committer Am I Evil? Yes, I Am!