为什么 __libc_start_main 的地址在 GDB 中始终相同，即使 ASLR 已打开？

Question

Breakpoint 1, 0x00007ffff7de8060 in __libc_start_main () from /usr/lib/libc.so.6
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /home/firstlove/projects/org-ioslide/example/a.out 

Breakpoint 1, 0x00007ffff7de8060 in __libc_start_main () from /usr/lib/libc.so.6
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /home/firstlove/projects/org-ioslide/example/a.out 

Breakpoint 1, 0x00007ffff7de8060 in __libc_start_main () from /usr/lib/libc.so.6
(gdb) Quit
(gdb) quit
A debugging session is active.

        Inferior 1 [process 16372] will be killed.

Quit anyway? (y or n) y
firstlove-pc% cat /proc/sys/kernel/randomize_va_space
2

IIUC，ASLR 应该随机化所有地址，包括libc.so ，但我发现__libc_start_main()在我的 Linux 机器上的地址总是0x00007ffff7de8060 ，为什么？ 怎么了？

Answer 1

当您在gdb运行程序时， gdb尝试通过禁用地址随机化来帮助您进行调试。 您可以使用以下命令启用它（从程序的下一次运行开始生效）：

set disable-randomization off