[GNAT 3.15p] Unexpected exception in Protected_Entry_Call

[GNAT 3.15p] Unexpected exception in Protected_Entry_Call

[Florian Weimer]

I'm seeing a strange exception raised by
System.Tasking.Protected_Objects.Operations.Protected_Entry_Call,
in this code:

      if Ceiling_Violation then

         --  Failed ceiling check

         Initialization.Undefer_Abort (Self_ID);
         raise Program_Error;
      end if;

The exception is apparently triggered by a simple conditional entry
call which is cancelled.  So far, I've only seen this issue on SMP
systems (more precisely: Linux/i386 and Linux/AMD64 (with 32-bit
userland) with NPTL).

The strange thing is that I don't use any fancy priorities, so I'm
surprised that the run-time system detects a ceiling violation.

Re: [GNAT 3.15p] Unexpected exception in Protected_Entry_Call

[Jean-Pierre Rosen]

Florian Weimer a �crit :
> I'm seeing a strange exception raised by
> System.Tasking.Protected_Objects.Operations.Protected_Entry_Call,
> in this code:
> 
>       if Ceiling_Violation then
> 
>          --  Failed ceiling check
> 
>          Initialization.Undefer_Abort (Self_ID);
>          raise Program_Error;
>       end if;
> 
> The exception is apparently triggered by a simple conditional entry
> call which is cancelled.  So far, I've only seen this issue on SMP
> systems (more precisely: Linux/i386 and Linux/AMD64 (with 32-bit
> userland) with NPTL).
> 
> The strange thing is that I don't use any fancy priorities, so I'm
> surprised that the run-time system detects a ceiling violation.
This rings an old bell...

I think that there was a bug in 3.15 around those lines, due to an 
unitialized priority in some data structure. Did you try it with a 
recent version of the compiler?

-- 
---------------------------------------------------------
            J-P. Rosen (rosen@adalog.fr)
Visit Adalog's web site at http://www.adalog.fr