[Crash-utility] User-land backtrace?

[Dave Anderson]

----- "Darrin Thompson" <darrinth at gmail.com> wrote:

> On Wed, Feb 24, 2010 at 12:21 PM, Dave Anderson < anderson at redhat.com
> > wrote:
> 
> 
> 
> That's right. That is the stack value that will be restored upon
> return to user-space, and the EIP will be restored to 00f14402.
> 
> One thing to make sure of is that when you do the "rd -u", you
> have set the crash utility to the context of the task whose "bt"
> output you're showing. "rd -u" will read the user space of the
> current task (i.e., the task shown if you do a "set" command).
> 
> Could that be adapted into a way to produce a userspace core dump that
> we could feed to regular old gdb?

This question comes up from time to time.

If all of a task's user pages were in memory (not swapped out), and
therefore in the vmcore -- which is becoming more and more unlikely 
with the use of makedumpfile to skip user pages altogether -- then
theoretically the kernel's elf_core_dump() function could basically
be "ported" to user-space.  I think... 

Anyway, I'm not particularly interested in doing it.  But it would
be an excellent candidate for an extension module if anybody's willing
to take it on.

Dave