Bug in rev 1.3 of sys/i386/linux/linux_ptrace.c

[Julian Elischer]

On Mon, 14 Apr 2003, John Baldwin wrote:

> In the linux_ptrace() function there is the following code:
> 
>         case PTRACE_GETFPXREGS: {
> #ifdef CPU_ENABLE_SSE
>                 struct proc *p;
>                 struct thread *td2;
> 
>                 ...
> 
>                 /* not being traced... */
>                 if ((p->p_flag & P_TRACED) == 0) {
>                         error = EPERM;
>                         goto fail;
>                 }
> 
>                 /* not being traced by YOU */
>                 if (p->p_pptr != td->td_proc) {
>                         error = EBUSY;
>                         goto fail;
>                 }
> 
>                 /* not currently stopped */
>                 if ((p->p_flag & (P_TRACED|P_WAITED)) == 0) {
>                         error = EBUSY;
>                         goto fail;
>                 }
> 
>                 ...
> 
> Now, since we've already checked P_TRACED above, this last
> check will never fail.  The diff in rev 1.3 was:
> 
> -               if (p->p_stat != SSTOP || (p->p_flag & P_WAITED) == 0) {
> +               if ((p->p_flag & (P_TRACED|P_WAITED)) == 0) {
> 
> So should this be (P_STOPPED|P_WAITED) instead?  Or maybe just
> (P_STOPPED_TRACE|P_WAITED)?

probably the 2nd option, except that I am not 100% sure without looking 
at the code, (which I don't have  alot of time for right now)
(you will sympathise more after June 4) (my Birthday BTW) that 
P_STOPPED_TRACE is fully implemented.. some other hands have been in
there and I haven't followed what they did..



> 
> -- 
> 
> John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
> "Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/
>