Re: [RFA][PATCH] Stack clash protection 06/08 - V4

[Jeff Law <law at redhat dot com>]

On 09/25/2017 08:14 AM, Segher Boessenkool wrote:
> On Mon, Sep 25, 2017 at 07:41:18AM -0500, Segher Boessenkool wrote:
>> On Mon, Sep 25, 2017 at 05:52:27AM -0500, Segher Boessenkool wrote:
>>> Bootstrap+testsuite finished on BE, but I forgot to enable stack-clash
>>> protection by default, whoops.  Will have results later today (also LE).
>>
>> Some new failures show up:
>>
>> +FAIL: c-c++-common/ubsan/vla-1.c   -O0  execution test
>>
>> /home/segher/src/gcc/gcc/testsuite/c-c++-common/ubsan/vla-1.c:18:7: runtime error: variable length array bound evaluates to non-positive value -1
>> /home/segher/src/gcc/gcc/testsuite/c-c++-common/ubsan/vla-1.c:24:7: runtime error: variable length array bound evaluates to non-positive value -1
>> /home/segher/src/gcc/gcc/testsuite/c-c++-common/ubsan/vla-1.c:24:7: runtime error: variable length array bound evaluates to non-positive value -1
>> /home/segher/src/gcc/gcc/testsuite/c-c++-common/ubsan/vla-1.c:30:7: runtime error: variable length array bound evaluates to non-positive value -1
>> /home/segher/src/gcc/gcc/testsuite/c-c++-common/ubsan/vla-1.c:30:7: runtime error: variable length array bound evaluates to non-positive value -1
>> /home/segher/src/gcc/gcc/testsuite/c-c++-common/ubsan/vla-1.c:30:7: runtime error: variable length array bound evaluates to non-positive value -1
>> /home/segher/src/gcc/gcc/testsuite/c-c++-common/ubsan/vla-1.c:36:7: runtime error: variable length array bound evaluates to non-positive value -5
>>
>> (both gcc and g++, both -m32 and -m64).
>>
>> This is BE; LE is still running.
> 
> LE show the same, but also
> 
>                 === acats tests ===
> +FAIL:  c52103x
> +FAIL:  c52104x
> +FAIL:  c52104y
> +FAIL:  cb1010a
> 
> These are
> 
> ---- C52103X CHECK THAT IN ARRAY ASSIGNMENTS AND IN SLICE ASSIGNMENTS,
>                 THE LENGTHS MUST MATCH; ALSO CHECK WHETHER
>                 CONSTRAINT_ERROR OR STORAGE_ERROR ARE RAISED FOR LARGE
>                 ARRAYS.
>    - C52103X NO CONSTRAINT_ERROR FOR TYPE WITH 'LENGTH = INTEGER'LAST + 
>                 3.
> 
> raised STORAGE_ERROR : stack overflow or erroneous memory access
> FAIL:	c52103x
This is expected.   stack clash protection does not guarantee we can run
the signal handler upon stack overflow -- thus we can not guarantee we
get the constraint error.


> 
> (twice)
> 
> ---- C52104Y CHECK THAT IN ARRAY ASSIGNMENTS AND IN SLICE ASSIGNMENTS,
>                 THE LENGTHS MUST MATCH.
>    - C52104Y NO CONSTRAINT_ERROR FOR NON-NULL ARRAY SUBTYPE WHEN ONE
>                 DIMENSION HAS INTEGER'LAST + 3 COMPONENTS.
> 
> raised STORAGE_ERROR : stack overflow or erroneous memory access
> FAIL:   c52104y
Likewise.


> 
> and,
> 
> ---- CB1010A CHECK THAT STORAGE_ERROR IS RAISED WHEN STORAGE ALLOCATED
>                 TO A TASK IS EXCEEDED.
>    - CB1010A CHECK TASKS THAT DO NOT HANDLE STORAGE_ERROR PRIOR TO
>                 RENDEZVOUS.
> FAIL:   cb1010a
Likewise.  We can't guarantee we can run the signal handler and thus we
can't inform the Ada runtime about the overflow.

Jeff