Vger broken w.r.t. gdb

[Daniel Jacobowitz]

On Thu, Jul 29, 1999 at 03:48:59PM +1000, Paul Mackerras wrote:
> Daniel Jacobowitz <drow at false.org> wrote:
> 
> > So my question is, what is at 0x3000c1a8?  It would appear, if I am not
> > misreading binfmt_elf.c, to be the program itself in its original
> > mmap'd location.  I'm not at all confident of that conclusion, though.
> 
> Cat /proc/<pid>/maps while you have the ls process stopped at an
> appropriate point.
> 
> > So regs->msr is actually from SRR1 of the running program?  Does it
> > generally get stuffed back into the MSR when that task is running?
> 
> Yep, but the high bits get ignored.

Now I'm really confused.

>From my readings it appears that we should only reach this point if a
trap instruction was encountered.  But from what I can see no trap
instruction exists at that address.  At
<http://www.them.org/~drow/check-core> is a core dump I obtained while
my system was in this confusing state; check-test in the same directory
is the program responsible.  The instruction appears to be in
_dl_debug_state from what I can tell, but no trap instruction was
present there.

Perhaps something having to do with instruction caching by the
processor?  This is a completely wild guess, but if a trap instruction
was encountered, and then gdb cleared it, and the instruction cache was
not flushed...

Dan

/--------------------------------\  /--------------------------------\
|       Daniel Jacobowitz        |__|        SCS Class of 2002       |
|   Debian GNU/Linux Developer    __    Carnegie Mellon University   |
|         dan at debian.org         |  |       dmj+ at andrew.cmu.edu      |
\--------------------------------/  \--------------------------------/

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