[Crash-utility] [PATCH] do not check sp if ip points to user space

[Dave Anderson]

----- Original Message -----

> >>>
> >>> And what happens when a backtrace is attempted on such a task?
> >>>
> >>> Since the current code would not set BT_USER_SPACE, I'm guessing that it
> >>> would run into this (at least on x86_64):
> >>>
> >>>         if (!(bt->flags & BT_USER_SPACE) && (!rsp || !accessible(rsp))) {
> >>>                 error(INFO, "cannot determine starting stack
> >>>                 pointer\n");
> >>>                 return;
> >>>         }
> >>
> >> Yes, crash will run into this on x86_64.
> > 
> > OK, so why not change the above to do something like this:
> > 
> >         if (!(bt->flags & BT_USER_SPACE) && (!rsp || !accessible(rsp))) {
> >                 fprintf(ofp, "cannot determine starting stack pointer\n");
> >                 if(KVMDUMP_DUMPFILE())
> >                         kvmdump_display_regs(bt->tc->processor,
> >                         ofp);
> >                 else if (ELF_NOTES_VALID() && DISKDUMP_DUMPFILE())
> >                         diskdump_display_regs(bt->tc->processor,
> >                         ofp);
> >                 else if (SADUMP_DUMPFILE()) {
> >                         sadump_display_regs(bt->tc->processor,
> >                         ofp);
> >                 return;
> >         }
> > 
> > Dave
> 
> Agree with it. But we should init ofp earlier, and we should add the
> same code in the function x86_back_trace_cmd().
> 
> Thanks
> Wen Congyang

Yes, I'll do that as well.

Thanks Wen,
  Dave