[Fortran][do concurrent] Runtime malloc error in saxpy.f90 with -stdpar flag

[hkvzjal]

Hi, I’m new to nvfortran compiler, I’m trying to test the do concurrent examples provided in the HPC SDK but I have a runtime error that I’m not sure how to handle:

I just took the saxpy.f90 example
Workstation: Windows PC with a GPU A6000 / compiling in WSL2 Ubuntu20.04 + hpc_sdk 2023

> nvfortran --version
nvfortran 23.1-0 64-bit target on x86-64 Linux -tp skylake-avx512

If I compile & run the saxpy example without -stdpar, everything goes fine. If I include -sdtpar

> nvfortran -stdpar -Minfo -fast saxpy.f90
saxpy_concurrent:
     35, Generated vector simd code for the loop
     36, FMA (fused multiply-add) instruction(s) generated
main:
     50, Loop not fused: function call before adjacent loop
         Generated vector simd code for the loop
     64, Loop not fused: function call before adjacent loop
         Generated vector simd code for the loop containing reductions

Runing the binary outputs:

> ./a.out
Current file:     /mnt/d/.../saxpy.f90
        function: saxpy_concurrent
        line:     26
This file was compiled: -acc=gpu -gpu=cc50 -gpu=cc60 -gpu=cc60 -gpu=cc70 -gpu=cc75 -gpu=cc80 -gpu=cc80 -
malloc(): invalid next size (unsorted)
Aborted

Where Line 26 corresponds to the “do concurrent” loop

Is this maybe a compatibility issue with the GPU? Any hints on how could I solve this?

Thanks!!

[MatColgrove]

Hi hkvzjal,

Likely what’s happening is that the runtime can’t find the CUDA driver. It’s typically installed in a non-default location on WSL2. To fix, set you’re environment’s LD_LIBRARY_PATH in to include the directory containing the CUDA driver, “libcuda.so”.

On my system, it’s in “/usr/lib/wsl/lib”, so I’d run “export LD_LIBRARY_PATH=/usr/lib/wsl/lib:$LD_LIBRARY_PATH” from the shell.

A good test is to run the ‘nvaccelinfo’ utility and if it finds the CUDA driver and prints out info on your device, then you should be good to run your program.

Hope this helps,
Mat

[hkvzjal]

@MatColgrove

export LD_LIBRARY_PATH=/usr/lib/wsl/lib:$LD_LIBRARY_PATH

Thank you!! It was exactly that :)