Re: [RFA/RFC 2] Remove hardware break and watchpoints at program exit.

Pierre Muller
2002-01-11T13:39:12Z

At 13:35 11/01/2002 , Eli Zaretskii a Ã©crit:
> > Date: Fri, 11 Jan 2002 13:00:44 +0100
> > From: Pierre Muller <muller@cerbere.u-strasbg.fr>
> >
> > In breakpoint_init_inferior
> > I added code that conditionally removes hardware watch and breakpoint
> > if the context is inf_exited, i.e. at exit of the debugged program.
>
>Thanks. I like this approach much better, especially because I never
>understood why does GDB do certain cleanups when the debuggee exits,
>but doesn't do other, similar cleanups.
>
> > I still kept the call to a generic hardware removal function
> > and testing the i386 case, I could see that even though the dr_mirror
> > array is zeored out, the dr_control_mirror and
> > dr_status_mirror still aren't set to zero.
> > For dr_control_register, this is due to an error in the I386_DR_DISABLE
> > because that macro only resets the active bit, but not the size and type bits
> > associated to that debug register.
>
>Why is this a problem? Once the active bit is off, the corresponding
>debug register is inactive, and its value is not important.

The code does already generate a claim for i386 linux:
the linux code tries to write the dr registers using ptrace
but as the process is already finished, this fails.
See i386-linux-nt.c line 741.

How could this be solved?
By adding a test
if (target_has_execution )
ptrace(....)

If this is correct, the same code should also be used for i386-bsd-nat.c

Pierre Muller
Institut Charles Sadron
6,rue Boussingault
F 67083 STRASBOURG CEDEX (France)
mailto:muller@ics.u-strasbg.fr
Phone : (33)-3-88-41-40-07 Fax : (33)-3-88-41-40-99