http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56471
janus at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |janus at gcc dot gnu.org
Summary|Program crashes when |Program crashes when
|allocating a derived type |allocating a derived type
|with a character |with an allocatable
|allocatable array |component
|component. |
--- Comment #1 from janus at gcc dot gnu.org 2013-02-27 11:55:37 UTC ---
Reduced test case:
program main
implicit none
type :: containerType
real, dimension(10000000) :: arrayData
integer, allocatable :: allo
end type
type (containerType),allocatable :: container
allocate(container)
end program
Note: The allocatable component does not have to be CHARACTER, but the array
needs to be very large in order to trigger the error. The generated code is:
container = 0B;
if ((logical(kind=4)) __builtin_expect ((integer(kind=8)) (container !=
0B), 0))
{
_gfortran_runtime_error_at (...);
}
else
{
container = (struct containertype *) __builtin_malloc (40000008);
if ((logical(kind=4)) __builtin_expect ((integer(kind=8)) (container
== 0B), 0))
{
_gfortran_os_error (...);
}
}
container->allo = 0B;
{
struct containertype containertype.0;
if (container != 0B) goto L.1;
container = (struct containertype *) __builtin_calloc (1, 40000008);
L.1:;
containertype.0.allo = 0B;
*container = containertype.0;
}
I don't really understand why 'container' is being allocated twice: Once with
__builtin_malloc and once with __builtin_calloc. Looks like we're leaking
memory here.
Valgrind reports:
==28612== Warning: client switching stacks? SP change: 0x7fefffbe0 -->
0x7fc9da1d0
==28612== to suppress, use: --max-stackframe=40000016 or greater
==28612== Invalid write of size 8
==28612== at 0x4008E5: MAIN__ (in /home/jweil/GSoC/PRs/56471/a.out)
==28612== by 0x4009D2: main (in /home/jweil/GSoC/PRs/56471/a.out)
==28612== Address 0x7fc9da1c8 is on thread 1's stack
==28612==
==28612== Can't extend stack to 0x7fc9d95e0 during signal delivery for thread
1:
==28612== no stack segment
==28612==
==28612== Process terminating with default action of signal 11 (SIGSEGV)
==28612== Access not within mapped region at address 0x7FC9D95E0
==28612== at 0x4008E5: MAIN__ (in /home/jweil/GSoC/PRs/56471/a.out)
==28612== If you believe this happened as a result of a stack
==28612== overflow in your program's main thread (unlikely but
==28612== possible), you can try to increase the size of the
==28612== main thread stack using the --main-stacksize= flag.
==28612== The main thread stack size used in this run was 8388608.
Indeed the segfault seems to be due to a stack overflow.
