Sigsev when trying to execute 32bit software

Sigsev when trying to execute 32bit software

[alexandre schenberg]

I am having problem when executing majority of 32bit software on my Linux.

This problem happens when running any dynamically linked c++ software and also dynamic linked c programs that uses any libs outside standard c libs. Only statically linked programs on both languages and the simplest c programs are able to execute.

For instance, this is what happens when executing a simple 32bit, dynamically linked c++ hello word on gdb:

"Program received signal SIGSEGV, Segmentation fault.
0x000044ae in ?? ()"

I compiled the program with: 
"g++ -m32 -o test-32bit test-32bit.cpp -Wl,--dynamic-link=/usr/lib32/ld-2.17.so"

and executed it with:

"LD_LIBRARY_PATH=/media/34GB/Arquivos-de-Programas-Linux/Gcc-4.9.4/lib32/ gdb ./test-32bit"

The same output is obtained when running 32bit programs that I built from the source, such as Dosbox and Snes9x.

The likely reason for this is that I decided to add 32bit support on my system. From the scratch.

First I built a 32bit glibc and installed it outside system tree of standard directories. Then I created a /usr/lib32 and put symbolic links there to everything in glibc's libdir. I also compiled a new gcc with multilib support (don't remember if that preceded glibc's install or not) and then created a symbolic link to libstdc++.so.6 also on /usr/lib/32.

Then I created sym links in /usr/local/bin to gcc and g++. Finally, I executed ldconfig.

A few other info that might prove useful:

"info shared" output:

Program received signal SIGSEGV, Segmentation fault.
0x000044ae in ?? ()
(gdb) info shared
From        To          Syms Read   Shared Object Library
0xf7fdb7e0  0xf7ff342c  Yes         /usr/lib32/ld-2.17.so
0xf7f24d70  0xf7f98aa8  No          /media/34GB/Arquivos-de-Programas-Linux/Gcc-4.9.4/lib32/libstdc++.so.6
0xf7e9c550  0xf7ec7c88  No          /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/libm.so.6
0xf7e7f000  0xf7e92ca8  No          /media/34GB/Arquivos-de-Programas-Linux/Gcc-4.9.4/lib32/libgcc_s.so.1
0xf7cd2280  0xf7dffa0c  No          /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/libc.so.6

If I execute a 64bit version of this c++ hello world I receive:
0x00007ffff7ddca80  0x00007ffff7df57c0  Yes         /lib64/ld-linux-x86-64.so.2

or a c hello world :
"0xf7fdb7e0  0xf7ff342c  Yes         /usr/lib32/ld-2.17.s" 

info proc mappings output:

"process 11686
Mapped address spaces:

	Start Addr   End Addr       Size     Offset objfile
	 0x8048000  0x8049000     0x1000        0x0 /media/34GB/demos/test-32bit
	 0x8049000  0x804a000     0x1000        0x0 /media/34GB/demos/test-32bit
	0xf7cb9000 0xf7cbb000     0x2000        0x0 
	0xf7cbb000 0xf7e76000   0x1bb000        0x0 /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/libc-2.17.so
	0xf7e76000 0xf7e79000     0x3000   0x1ba000 /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/libc-2.17.so
	0xf7e79000 0xf7e7b000     0x2000   0x1bd000 /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/libc-2.17.so
	0xf7e7b000 0xf7e7d000     0x2000        0x0 
	0xf7e7d000 0xf7e97000    0x1a000        0x0 /media/34GB/Arquivos-de-Programas-Linux/Gcc-4.9.4/lib32/libgcc_s.so.1
	0xf7e97000 0xf7e98000     0x1000    0x19000 /media/34GB/Arquivos-de-Programas-Linux/Gcc-4.9.4/lib32/libgcc_s.so.1
	0xf7e98000 0xf7edd000    0x45000        0x0 /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/libm-2.17.so
	0xf7edd000 0xf7edf000     0x2000    0x45000 /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/libm-2.17.so
	0xf7edf000 0xf7fcc000    0xed000        0x0 /media/34GB/Arquivos-de-Programas-Linux/Gcc-4.9.4/lib32/libstdc++.so.6.0.20
	0xf7fcc000 0xf7fd1000     0x5000    0xed000 /media/34GB/Arquivos-de-Programas-Linux/Gcc-4.9.4/lib32/libstdc++.so.6.0.20
	0xf7fd1000 0xf7fda000     0x9000        0x0 
	0xf7fda000 0xf7fdb000     0x1000        0x0 [vdso]
	0xf7fdb000 0xf7ffc000    0x21000        0x0 /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/ld-2.17.so
	0xf7ffc000 0xf7ffe000     0x2000    0x20000 /media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/lib/ld-2.17.so
	0xfffe9000 0xffffe000    0x15000        0x0 [stack]"

 How I (probably compiled) glibc:
"CC="gcc -m32 -march=core2 -mtune=core2 -O2" ../configure --prefix=/media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/ --build=x86_64-linux-gnu --host=i686-gnu-linux --enable-kernel-2.6.32 --enable-profile"

How I (probably) compiled the 64bit glibc that my system is currently using:
CC="gcc -march=native -mtune=native -O2" ../configure --prefix=/usr/ --enable-kernel=2.6.32

So, what I need right now, are suggestions of ways to debug this test example (or the other 32bit software) as to figure out the cause and then try to fix it.

Re: Sigsev when trying to execute 32bit software

[Xi Ruoyao]

On Sat, 2023-05-20 at 15:26 -0300, alexandre schenberg via Gcc-help
wrote:
> "CC="gcc -m32 -march=core2 -mtune=core2 -O2" ../configure --
> prefix=/media/34GB/Arquivos-de-Programas-Linux-32bit/Glibc-2.17/ --
> build=x86_64-linux-gnu --host=i686-gnu-linux --enable-kernel-2.6.32 --
> enable-profile"

According to Glibc wiki [1] building Glibc with any prefix other than
/usr is not supported.

[1]: https://sourceware.org/glibc/wiki/Testing/Builds

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University