memory-leaks - Ada任务声明导致内存泄漏

Question

我有以下小 Ada 程序:

procedure Leaky_Main is 
   task Beer;
   task body Beer is 
   begin 
      null;
   end Beer;
begin 
   null;
end Leaky_Main;

一切都相当基本，但是当我像这样编译时:

gnatmake -g -gnatwI leaky_main.adb

并通过 Valgrind 运行它，如下所示:

valgrind --tool=memcheck -v --leak-check=full --read-var-info=yes --leak-check=full --show-reachable=yes ./leaky_main

我收到以下错误摘要:

==2882== 2,104 bytes in 1 blocks are still reachable in loss record 1 of 1
==2882==    at 0x4028876: malloc (vg_replace_malloc.c:236)
==2882==    by 0x42AD3B8: __gnat_malloc (in /usr/lib/i386-linux-gnu/libgnat-4.4.so.1)
==2882==    by 0x40615FF: system__task_primitives__operations__new_atcb (in /usr/lib/i386-linux-gnu/libgnarl-4.4.so.1)
==2882==    by 0x406433C: system__tasking__initialize (in /usr/lib/i386-linux-gnu/libgnarl-4.4.so.1)
==2882==    by 0x4063C86: system__tasking__initialization__init_rts (in /usr/lib/i386-linux-gnu/libgnarl-4.4.so.1)
==2882==    by 0x4063DA6: system__tasking__initialization___elabb (in /usr/lib/i386-linux-gnu/libgnarl-4.4.so.1)
==2882==    by 0x8049ADA: adainit (b~leaky_main.adb:142)
==2882==    by 0x8049B7C: main (b~leaky_main.adb:189)
==2882== 
==2882== LEAK SUMMARY:
==2882==    definitely lost: 0 bytes in 0 blocks
==2882==    indirectly lost: 0 bytes in 0 blocks
==2882==      possibly lost: 0 bytes in 0 blocks
==2882==    still reachable: 2,104 bytes in 1 blocks
==2882==         suppressed: 0 bytes in 0 blocks
==2882== 
==2882== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 21 from 6)
--2882-- 
--2882-- used_suppression:     21 U1004-ARM-_dl_relocate_object
==2882== 
==2882== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 21 from 6)

有谁知道为什么这被报告为错误？ 我相当确定没有实际泄漏，但我想知道为什么/如何发生。

谢谢

Answer 1

有问题的分配看起来是任务控制 block (TCB)。任务完成后必须保留此信息，以便您可以说

if Beer’Terminated then
   ...

所以我认为这可能是 valgrind 进行检查时的人为因素。

我只在分配任务的地方遇到过这种情况；必须等到'Termied为True才释放任务，或者GNAT愉快地释放堆栈但默默地没有释放TCB，导致真正的泄漏，例如你的。 AdaCore 最近修复了这个问题(我没有引用资料，它在他们的开发者日志中)。