带有 -fopenmp 的段错误，用于一个简单的程序 [英] segfault with -fopenmp for a trivial program

问题描述

我正在刷新 openmp，并陷入了这种奇怪的情况.剃掉一堆，我创建了这个显示问题的最小的琐碎案例

I am refreshing openmp a bit, and got into this weird situation. Shaved off the bunch, I created this minimal trivial case that shows the issue

program ex2
    implicit none
    integer, parameter :: n=10000000
    integer :: i
    real :: x(n)

    do i=1,n
        x(i) = 0.0d0
    enddo

end program

没有指定标志，mac (10.6) 上的 gfortran 4.3.4 编译，程序正确执行.

with no flags specified, gfortran 4.3.4 on the mac (10.6) compiles, and the program executes correctly.

但是，如果我使用 -fopenmp 启用 openmp，程序会因分段错误而终止.显然，没有代码被执行，因为它立即崩溃.如您所见，openmp 从未在代码中用于并行化任何内容.我尝试修改堆栈大小，都使用ulimit -fmax-stack-var-size，无论如何，千万实数不是我定义的大数组.

However, if I enable openmp with -fopenmp, the program terminates with segmentation fault. No code get executed, apparently, as it crashes immediately. As you see, openmp is never used in the code to parallelize anything. I tried to modify the stack size, both with ulimit the -fmax-stack-var-size, and in any case, ten millions reals is not what I define a big array.

我做错了什么?

推荐答案

是的，openmp 通常会改变内存的分配方式.之前的讨论:OpenMP in Fortran

Yes, openmp typically changes how memory is allocated. A previous discussion: OpenMP in Fortran

在网上搜索，我发现 http://homepage.mac.com/eric.c/hpc/contents/documentation/How%20to%20increase%20the%20stack%20size%20on%20Mac%20OS%20X.pdf

gfortran-mp-4.3 -fopenmp ex2.f90 -Wl,-stack_size,0x40000000,-stack_addr,0xf0000000 -o ex2.exe

gfortran-mp-4.3 -fopenmp ex2.f90 -Wl,-stack_size,0x40000000,-stack_addr,0xf0000000 -o ex2.exe

修复了我的 Mac 上的问题.

fixed the problem on my Mac.

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