[PATCH 1/2] avoid infinite loop with bad debuginfo

[Tom Tromey]

Pedro> I don't think so, because get_prev_frame_1 would not link in
Pedro> the dup frame.  The loop in question would never see it.

Pedro> Hmm, I think one of us is missing something.

Haha, yeah, that usually means me :-)

No worries.  I think I understand this bit now.

Pedro> So the bad loop can only ever happen (outside the unwinder code)
Pedro> if we ever let outselves get in the dup frame_id situation:

>> #4  0x0000007fb7f0956c in clone () from /lib64/libc.so.6
>> #5  0x0000007fb7f0956c in clone () from /lib64/libc.so.6
>> Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Pedro> At least, I'm not seeing any other way.

Yes, I see now.

Really not looking forward to writing the test.

Tom