[Qemu-discuss] 3.1.0 throws *** stack smashing detected *** or SIGSEGV

[Dennis Clarke]

Somewhat a baffling situation here. I have Debian buster x86_64 running
just fine and also the default qemu packages from the Debian folks.
However those are 2.12.0 whereas my own local builds from the 3.1.0
sources are the current prod release. Needless to say I was quite happy
to create a blank 32g qcow2 disk image and then used the Debian qemu
binary qemu-system-x86_64 to install a test debian machine thus :

nix $ $HOME/local/bin/qemu-img create -f qcow2 \
> -o cluster_size=65536 -o preallocation=full q310_x86_64.img 32g
Formatting 'q310_x86_64.img', fmt=qcow2 size=34359738368 
cluster_size=65536 preallocation=full lazy_refcounts=off refcount_bits=16
nix $

Then install with :

nix $ /usr/bin/qemu-system-x86_64 \
> -machine q35 -cpu qemu64 -smp sockets=2 -m 4G \
> -drive file=q310_x86_64.img,format=qcow2,id=hd0 \
> -boot once=d \
> -cdrom $HOME/resources/debian-testing-amd64-DVD-1.iso
nix $

Smooth. A bit slow but smooth.

Any attempt to install with the 3.1.0 version would throw a SIGSEGV :

[144646.710186] show_signal_msg: 6 callbacks suppressed
[144646.710188] qemu-system-x86[17501]: segfault at 0 ip 
0000000000000000 sp 00007ffb28003f98 error 14 in 
qemu-system-x86_64[55aaa78a1000+2a3000]
[144646.710195] Code: Bad RIP value.

No idea what to make of that.

The install goes smooth and boots and runs fine.  No working network yet
however that can be sorted out later. Any attempt to start up that guest
with the 3.1.0 bins results in the fascinating :

nix $ $HOME/local/bin/qemu-system-x86_64 \
> -machine q35 -cpu qemu64 -smp sockets=2 -m 4G \
> -drive file=q310_x86_64.img,format=qcow2,id=hd0
VNC server running on 127.0.0.1:5900
*** stack smashing detected ***: <unknown> terminated
Aborted
nix $

Interesting.

My config line for qemu 3.1.0 was :

nix $ ./configure \
> --prefix=/home/dclarke/local \
> --cc=/usr/bin/gcc-8 --cxx=/usr/bin/g++-8 \
> --python=/usr/bin/python --enable-debug \
> --disable-xen --enable-debug-info \
> --enable-bsd-user --enable-libssh2 --disable-strip

That went smoothly and builds fine.  Never seems to run or do anything
other than SIGSEGV or perhaps the above 'stack smashing'.  Any thoughts
on what is the cause of this bizarre behavior ?

Dennis