将内部函数作为参数传递时出现分段错误 [英] Segmentation fault when passing internal function as argument
问题描述
我有一些代码将主程序的内部函数作为函数的参数传递:当最终调用传递的函数时，它将导致分段错误.仅当我将Windows子系统用于Linux(在WSL上使用Ubuntu 16)时，才会发生这种情况.在本机Linux或Mac计算机上运行时不会发生这种情况.
一个崩溃的最小示例:
module test1
implicit none
contains
subroutine x(ff,y)
interface
real function ff(y)
real, intent(in) :: y
end function ff
end interface
real, intent(in) :: y
integer z
z=ff(y)
end subroutine x
end module test1
program tester
use test1
implicit none
call x(f,1.0)
contains
real function f(y)
real, intent(in) :: y
write(*,*) y
f=y*y
end function f
end program tester
编译:
gfortran-7 -ggdb test_fun_passing.f90 -o test
回溯，gdb输出:
(gdb) bt
#0 0x00007ffffffde320 in ?? ()
#1 0x0000000000400734 in test1::x (ff=0x7ffffffde320, y=1) at test_fun_passing.f90:17
#2 0x0000000000400829 in tester () at test_fun_passing.f90:31
#3 0x0000000000400860 in main (argc=1, argv=0x7ffffffde64f) at test_fun_passing.f90:27
#4 0x00007ffffec70830 in __libc_start_main (main=0x40082c <main>, argc=1, argv=0x7ffffffde448, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffffffde438) at ../csu/libc-start.c:291
#5 0x0000000000400669 in _start ()
此功能确实有效(将f移动到其自己的模块中，但仍作为参数传递)，因此它与f被包含在程序中有关.
module test1
implicit none
contains
subroutine x(ff,y)
interface
real function ff(y)
real, intent(in) :: y
end function ff
end interface
real, intent(in) :: y
integer z
z=ff(y)
end subroutine x
end module test1
module test2
implicit none
contains
real function f(y)
real, intent(in) :: y
write(*,*) y
f=y*y
end function f
end module test2
program tester
use test1
use test2
implicit none
call x(f,1.0)
end program tester
gfortran-7 -ggdb test_fun_passing.f90 -o test && ./test
1.00000000
以这种方式传递f是有效的Fortran，还是我正在中继本机Linux上的某些非标准功能?
好像我遇到了这个问题:
https://github.com/Microsoft/WSL/issues/3083 和 https://github.com/Microsoft/WSL/issues/286
WSL具有不可执行的堆栈.正在运行:
excestack -c test
在本机linux上，
要从二进制文件中删除execstack，将触发与我在WSL上相同的错误消息.在WSL上清除/设置execstack(使用-c/-s)不会执行任何操作.从github错误报告看来，它似乎不太可能得到解决.
I have some code that passes an internal function of the main program as an argument to a function: when the function that been passed is eventually called it causes a segmentation fault. This only occurs when I use Windows Subsystem for Linux (I'm using Ubuntu 16 on WSL); running on native Linux or Mac machines this does not occur.
A minimal example that crashes:
module test1
implicit none
contains
subroutine x(ff,y)
interface
real function ff(y)
real, intent(in) :: y
end function ff
end interface
real, intent(in) :: y
integer z
z=ff(y)
end subroutine x
end module test1
program tester
use test1
implicit none
call x(f,1.0)
contains
real function f(y)
real, intent(in) :: y
write(*,*) y
f=y*y
end function f
end program tester
Compiled with:
gfortran-7 -ggdb test_fun_passing.f90 -o test
The backtrace, gdb output:
(gdb) bt
#0 0x00007ffffffde320 in ?? ()
#1 0x0000000000400734 in test1::x (ff=0x7ffffffde320, y=1) at test_fun_passing.f90:17
#2 0x0000000000400829 in tester () at test_fun_passing.f90:31
#3 0x0000000000400860 in main (argc=1, argv=0x7ffffffde64f) at test_fun_passing.f90:27
#4 0x00007ffffec70830 in __libc_start_main (main=0x40082c <main>, argc=1, argv=0x7ffffffde448, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffffffde438) at ../csu/libc-start.c:291
#5 0x0000000000400669 in _start ()
This one does work (moving f into its own module but still passing as an argument) so it's something about f being contained in the program.
module test1
implicit none
contains
subroutine x(ff,y)
interface
real function ff(y)
real, intent(in) :: y
end function ff
end interface
real, intent(in) :: y
integer z
z=ff(y)
end subroutine x
end module test1
module test2
implicit none
contains
real function f(y)
real, intent(in) :: y
write(*,*) y
f=y*y
end function f
end module test2
program tester
use test1
use test2
implicit none
call x(f,1.0)
end program tester
gfortran-7 -ggdb test_fun_passing.f90 -o test && ./test
1.00000000
Is passing f in this way valid Fortran, or have I been relaying on some non-standard feature on native Linux?
Looks like I'm running into this:
https://github.com/Microsoft/WSL/issues/3083 and https://github.com/Microsoft/WSL/issues/286
WSL has a non-executable stack. Running:
excestack -c test
on native linux, to remove the execstack from the binary, triggers the same error message as I have on WSL. Clearing/setting the execstack (with -c/-s) on WSL does nothing. From the github bug report it seems its unlikely to be fixed.
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