internal-error: insert_step_resume_breakpoint_at_sal

[Andrew Cagney]

Nick Roberts wrote:
>  > What's at $pc (where PC is 0x4012e7e9 or 0x80850d5), symtab==0 indicates 
>  > a symtab lookup failure.
> 
> See my earlier message to Dave Korn.
> 
>  > >  > Can you capture the output from "set debug infrun 1"?  It should help.
>  > > 
>  > > See below. I can send the full transcript if necessary.
>  > 
>  > How much more?
> 
> Well its only the stuff before I type "next" i.e. Emacs starting up and
> lots of:
> 
>  ...
>  infrun: TARGET_WAITKIND_STOPPED
>  infrun: stop_pc = 0x4012e7e9
>  infrun: random signal 20
>  infrun: resume (step=0, signal=20)
>  infrun: prepare_to_wait
>  infrun: infwait_normal_state
>  infrun: TARGET_WAITKIND_STOPPED
>  infrun: stop_pc = 0x4012e7e9
>  infrun: random signal 20
>  ...
> 
>  > There appears to be stuff missing here, the output should contain 
>  > something like:
>  > 
>  > 	resume(step=1, signal=0)
>  > 	resume(step=0, signal=0)
>  > 
>  > as GDB single-steps the thread off breakpoint 3.  The PC should be near 
>  > or at 0x80850d5 found in the below.
> 
> Thats much earlier. I attach the full transcript below.
> 
> Maybe its too hard to debug over the Internet as I don't understand the
> internals well enough. It doesn't seem to be causing a problem for anybody
> else and I can get round it in the way I suggested in my first message.

Tracking down these sorts of bugs is really important - it makes the 
difference between a toy and a real debugger, and I think your efforts 
have paid off :-)

With the log you provided I've been able to identify one bug - 
back-to-back signals (where the inferior was receiving the next signal 
just as the previous handler returned) would lead to a panic.

I'm about to commit a testcase and fix.

thanks,
Andrew