[RFA] fix crasher on detach command

[Michael Snyder]

Pedro Alves wrote:
> On Monday 07 June 2010 19:11:02, Michael Snyder wrote:
>> Hi,
>>
>> The circumstances are, detach from a remote target that doesn't have
>> threads.  Remote.c leaves the PID arbitrarily as "42000", and
>> target_detach calls remove_breakpoints_pid, which crashes because
>> find_inferior_pid returns NULL.
> 
> It shouldn't matter that the PID is arbitrary; there should be an
> inferior with that PID in the inferior list.  This probably means
> that the inferior got its PID cleared to 0 already when you get here?
> How?

It was a bad connect, which aborted part way through.
So yes, we're in an inconsistent internal state.


> What's the backtrace like at the time of the crash?  I assume
> the remove_breakpoints_pid call is coming from within target_detach?

It's fairly normal, target_detach is called by detach_command.