Re: [2/3] 2.6.22-rc2: known regressions v2

On Fri, 25 May 2007, Alan Cox wrote:
> 
> There is an additional factor - dumps contain data which variously is -
> copyright third parties, protected by privacy laws, just personally
> private, security sensitive (eg browser history) and so on.

Yes. 

I'm sure we've had one or two crashdumps over the years that have actually 
clarified a bug.

But I seriously doubt it is more than a handful. 

> Diskdump (and even more so netdump) are useful in the hands of a
> developer crashing their own box just like kgdb, but not in the the
> normal and rational end user response of  "its broken, hit reset"

Amen, brother.

Even for developers, I suspect a _lot_ of people end up doing "ok, let's 
bisect this" or some other method to narrow it down to a specific case, 
and then staring at the source code once they get to that point.

At least I hope so. Even in user space, you should generally use gdb to 
get a traceback and perhaps variable information, and then go look at the 
source code.

Yes, dumps can (in theory) be useful for one-off issues, but I doubt many 
people have ever been able to get anything much more out of them than from 
a kernel "oops" message. 

For developers, I can heartily recommend the firewire-based remote debug 
facilities that the PowerPC people use. I've used it once or twice, and it 
is fairly simple and much better than a full dump (adn it works even when 
the CPU is totally locked up, which is the best reason for using it).

But 99% of the time, the problem doesn't happen on a developer machine, 
and even if it does, 90% of the time you really just want the traceback 
and register info that you get out of an oops.

			Linus