I'm not sure if a simple test case exists - this bugs seems to manifest
in fairly unusual scenarios. We experienced this while creating "mex"
modules for Matlab.
Using this trivial example (test.c):
#include <omp.h>
#include "mex.h"
void mexFunction( int nlhs, mxArray *plhs[],
int nrhs, const mxArray *prhs[] )
{
int nthreads, tid;
#pragma omp parallel private(nthreads, tid)
{
tid = omp_get_thread_num();
printf("Hello World from thread = %d\n", tid);
if (tid == 0)
{
nthreads = omp_get_num_threads();
printf("Number of threads = %d\n", nthreads);
}
}
}
And compiling with:
gcc -fopenmp -fPIC -o test.mexa64 -shared -I/opt/matlab/extern/include test.c
We get the following error:
$ export OMP_NUM_THREADS=4; echo "test" | matlab -nodisplay
>> ??? Invalid MEX-file
'/home/user/testmex/test.mexa64':
/usr/lib/libgomp.so.1: cannot allocate memory in static TLS block.
This is with gcc-4.2-base and libgomp1 4.2.4-1ubuntu3
After upgrading to gcc-4.2-base and libgomp1 4.2.4-1ubuntu4, the code
works properly:
$ export OMP_NUM_THREADS=4; echo "test" | matlab -nodisplay
>> Hello World from thread = 1
Hello World from thread = 3
Hello World from thread = 2
Hello World from thread = 0
Number of threads = 4
So, at least for this specific case of a Matlab mex module dynamically
linked to libgomp, 4.2.4-1ubuntu4 fixes the problem.
I hope this helps...
--
Please apply libgomp patch to GCC for Hardy Heron
https://bugs.launchpad.net/bugs/235070
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