This simple testcase:
#include <unistd.h>
void _start(void) {
_exit(0);
}
crashes when run on Debian 12.6 i386.
Compiled with gcc -lc -nostdlib -static -Os. Note that this is on an i386 version of Debian.
In gdb:
0x804905b <_exit+59> call *%gs:0x10
$gs is 0.
It still crashes if I remove the call to _exit.
Is Debian i386 borked when it comes to running static exes without main? I have no problem on amd64 systems (FreeBSD 14.0 with clang and Fedora 39). Also no problem on FreeBSD when compiling for i386.
UPDATE: On Fedora 39 amd64 glibc 2.39 GCC 14.2.1, same problem.
In the manual page of exit according to the following:
Up to glibc 2.3, the _exit() wrapper function invoked the kernel system call of the same name. Since glibc 2.3, the wrapper function invokes exit_group(2), in order to terminate all of the threads in a process.
the _exit function needs to call a library function with the 2.3 version of glibc. I think debian 12.6 uses glibc 2.3 and other systems you mentioned uses a prior version. However, I am not sure how you were able to compile it statically if this is the case.