Comment 3 for bug 1462640

I can confirm that this bug still exists in the current qemu master (short commit ID 0050f9978e):

~/qemu$ gcc -m32 shm_bug.c -o shm_bug32
shm_bug.c: In function ‘main’:
shm_bug.c:12:24: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
       const void *at = 0x7f7df38ea000;
                        ^~~~~~~~~~~~~~
~/qemu$ i386-linux-user/qemu-i386 ./shm_bug32
got err 0, ptr 0xffffffff
ari@ari-thinkpad:~/qemu$ gcc shm_bug.c -o shm_bug64
shm_bug.c: In function ‘main’:
shm_bug.c:12:24: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
       const void *at = 0x7f7df38ea000;
                        ^~~~~~~~~~~~~~
~/qemu$ x86_64-linux-user/qemu-x86_64 ./shm_bug64
got err 0, ptr 0x7f7df38ea000
ari@ari-thinkpad:~/qemu$

Additionally, running each executable directly on a 64-bit Ubuntu 18.04 system, we can see that the behavior of the 32-bit binary differs between qemu-i386 and native, while that of the 64-bit binary does not:

~/qemu$ ./shm_bug32
got err 0, ptr 0xf38ea000
~/qemu$ ./shm_bug64
got err 0, ptr 0x7f7df38ea000
~/qemu$