[Crash-utility] Why are there two ways of getting register values for active tasks?

[Dave Anderson]

----- "Daisuke HATAYAMA" <d.hatayama at jp.fujitsu.com> wrote:

> Hi, all.
> 
> I have a question on the implementation of get_netdump_regs_x86_64().
> 
> Currently, in order to get register values for active tasks, only
> panic task makes use of note information. On the other hand, other
> active tasks search stack frame for registers saved at nmi
> switch. However, crash dump contains the note information for every
> CPUs, so I think it uncessary to search stack frame.

Originally it was done that way because the code was written for 
netdump-generated dumpfiles, which only generated note information
for the panic task.  But if I'm not mistaken, given that recent
kernels do not store debuginfo data for the user_regs_struct, it
almost always falls through into x86_64_get_stack_frame(). 

Dave