"Uninitialised value was created by a stack allocation" 使用 NAG fortran 6.2

Question

我在最新版本的 NAG Fortran Compiler Release 6.2(Chiyoda) Build 6214 中遇到了一个非常奇怪的行为。当使用 ifort 或 gfortran 时一切正常，甚至使用 NAG Fortran Compiler Release 6.1(Tozai) Build 6136。以下代码重现了我遇到的错误：

module mod
  type :: type1_t
  end type type1_t

  type :: type2_t
  contains
    procedure, nopass :: proc2
  end type type2_t
contains
  subroutine proc2
    class(type1_t), allocatable :: bug
  end subroutine proc2
end module mod

program main
  use mod
  type(type2_t) :: type2
  call type2 % proc2
end program main

基本上，问题似乎出在过程 proc2 中的局部变量 bug 中。我在使用 Valgrind 时收到以下错误报告：

==22467== ERROR SUMMARY: 26 errors from 9 contexts (suppressed: 0 from 0)
==22467== 
==22467== 1 errors in context 1 of 9:
==22467== Syscall param write(buf) points to uninitialised byte(s)
==22467==    at 0x5710154: write (write.c:27)
==22467==    by 0x568B1BC: _IO_file_write@@GLIBC_2.2.5 (fileops.c:1203)
==22467==    by 0x568BB2E: new_do_write (fileops.c:457)
==22467==    by 0x568BB2E: _IO_file_xsputn@@GLIBC_2.2.5 (fileops.c:1277)
==22467==    by 0x567F2AE: fputs (iofputs.c:38)
==22467==    by 0x16E42B: write_insertion (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x16FFC7: rt_message_core.constprop.7 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x17163D: __NAGf90_rterr (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x121CD8: line_deallocate.isra.2 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x123E98: __NAGf90_laDeAlloc (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x15FEDB: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Address 0x1ffeffe969 is on thread 1's stack
==22467==  in frame #4, created by write_insertion (???:)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 1 errors in context 2 of 9:
==22467== Conditional jump or move depends on uninitialised value(s)
==22467==    at 0x4C32CF9: strlen (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22467==    by 0x567F204: fputs (iofputs.c:33)
==22467==    by 0x16E42B: write_insertion (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x16FFC7: rt_message_core.constprop.7 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x17163D: __NAGf90_rterr (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x121CD8: line_deallocate.isra.2 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x123E98: __NAGf90_laDeAlloc (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x15FEDB: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 1 errors in context 3 of 9:
==22467== Use of uninitialised value of size 8
==22467==    at 0x121C48: line_deallocate.isra.2 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x123E98: __NAGf90_laDeAlloc (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x15FEDB: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 1 errors in context 4 of 9:
==22467== Conditional jump or move depends on uninitialised value(s)
==22467==    at 0x127C63: __NAGf90_cdangling_aDeAlloc (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x15FEDB: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 1 errors in context 5 of 9:
==22467== Use of uninitialised value of size 8
==22467==    at 0x15FEA9: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 1 errors in context 6 of 9:
==22467== Use of uninitialised value of size 8
==22467==    at 0x15FE96: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 1 errors in context 7 of 9:
==22467== Conditional jump or move depends on uninitialised value(s)
==22467==    at 0x15FE90: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 9 errors in context 8 of 9:
==22467== Conditional jump or move depends on uninitialised value(s)
==22467==    at 0x4C32D08: strlen (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22467==    by 0x567F204: fputs (iofputs.c:33)
==22467==    by 0x16E42B: write_insertion (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x16FFC7: rt_message_core.constprop.7 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x17163D: __NAGf90_rterr (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x121CD8: line_deallocate.isra.2 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x123E98: __NAGf90_laDeAlloc (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x15FEDB: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== 
==22467== 10 errors in context 9 of 9:
==22467== Conditional jump or move depends on uninitialised value(s)
==22467==    at 0x16EAD1: write_insertion (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x16FFC7: rt_message_core.constprop.7 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x17163D: __NAGf90_rterr (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x121CD8: line_deallocate.isra.2 (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x123E98: __NAGf90_laDeAlloc (in /home/rcarvalho/Desktop/nagdebug/a.out)
==22467==    by 0x15FEDB: mod_MP_proc2 (test.f90:12)
==22467==    by 0x15FF54: main (test.f90:18)
==22467==  Uninitialised value was created by a stack allocation
==22467==    at 0x15FBA4: mod_MP_proc2 (test.f90:10)
==22467== 
==22467== ERROR SUMMARY: 26 errors from 9 contexts (suppressed: 0 from 0)
Aborted (core dumped)

对理解这种行为有什么建议吗？或者我做错了什么...

Answer 1

显然这个问题已经在补丁 6218 中解决了，因为“本地多态标量可能导致运行时崩溃如果在执行例程期间局部变量未分配，则可分配没有类型参数。”

"Uninitialised value was created by a stack allocation" 使用 NAG fortran 6.2

"Uninitialised value was created by a stack allocation" with NAG fortran 6.2

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