qemu quits when pressing ctrl-c in gdb - gdb

Question

Debugging my own kernel with qemu and gdb seems to be unnecessarily hard because pressing ctrl-c in gdb to break qemu does not break it, but makes it quit with the message
qemu-system-x86_64: terminating on signal 2
[Inferior 1 (Remote target) exited normally]
qemu command line:
qemu-system-x86_64 -s -no-shutdown -no-reboot -enable-kvm -m 1G -smp cores=1 -cpu qemu64 -drive if=pflash,format=raw,file=ovmf/OVMF.fd -drive file=fat:rw:hda,format=raw -net none -debugcon file:debug.log -global isa-debugcon.iobase=0x402 &
The behavior is the same without KVM. Could someone please help, how to solve this?
qemu-system-x86_64 v3.1.0
gdb v8.2.1
I would like not to build the latest versions of these from source as it seems to be a daunting task to do.
EDIT: Created a minimal environment where the issue can be reproduced. I may have tracked it down to running the whole thing from a shell script, but can't seem to progress further. Commenting out the gdb call in the script and starting it from a separate terminal, solves the issue (however i like things that work with as few keystrokes as possible).
You can download it here.
Just start the script called qd
(Is there a nicer way to provide files? I will delete this after a while.)

Answer 1

I tested with QEMU 5.0.0 and GDB 9.2, same issue, and same solution, that is commenting out the GDB call in the script and starting it from a separate terminal. You could probably just modify your script so that QEMU would be started in another
terminal. Starting QEMU using nohup is not working either.
I included the script I am usually using for building fresh versions of QEMU and GDB: latest versions are likely to have fixed bugs. The script is working on Ubuntu 20.04, and is probably still working on 16.04 and 18.04 - you may have to make small adjustments at the beginning of the script. Feel free to report issues, I would be willing to fix them.
build-qemu-gdb.sh:
#!/bin/bash
set -e
# Xenial/16.04
PERL_MODULES_VERSION=5.22
SPHINX=python-sphinx
# Bionic/18.04
PERL_MODULES_VERSION=5.26
SPHINX=python-sphinx
# Focal/20.04
PERL_MODULES_VERSION=5.30
SPHINX="sphinx-doc sphinx-common"
# Qemu
QEMU_VERSION=5.0.0
PREFIX=/opt/qemu-${QEMU_VERSION}
# GDB
GDB_VERSION=9.2
do_get_gdb()
{
if [ -f gdb-${GDB_VERSION}.tar.xz ]
then
echo "gdb-${GDB_VERSION}.tar.xz is present."
else
wget http://ftp.gnu.org/gnu/gdb/gdb-${GDB_VERSION}.tar.xz
fi
}
do_get_qemu()
{
if [ -f qemu-${QEMU_VERSION}.tar.xz ]
then
echo "qemu-${QEMU_VERSION}.tar.xz is present."
else
wget https://download.qemu.org/qemu-${QEMU_VERSION}.tar.xz
fi
}
do_install_prerequisites()
{
sudo apt-get install libglib2.0-dev libfdt-dev libpixman-1-dev zlib1g-dev libaio-dev libbluetooth-dev libbrlapi-dev libbz2-dev libcap-dev libcap-ng-dev libcurl4-gnutls-dev libgtk-3-dev libibverbs-dev \
libjpeg8-dev libncurses5-dev libnuma-dev librbd-dev librdmacm-dev libsasl2-dev libsdl2-dev libseccomp-dev libsnappy-dev libssh2-1-dev libvde-dev libvdeplug-dev libvte-2.91-dev libxen-dev liblzo2-dev \
valgrind xfslibs-dev liblzma-dev flex bison texinfo gettext perl perl-modules-${PERL_MODULES_VERSION} ${SPHINX}
}
do_configure()
{
local TARGET_LIST="x86_64-softmmu"
pushd qemu-${QEMU_VERSION}
./configure --target-list="${TARGET_LIST}" --prefix=${PREFIX} --extra-cflags="-I$(pwd)/packages/include" --extra-ldflags="-L$(pwd)/packages/lib"
popd
}
do_extract_qemu()
{
echo "extracting QEMU..."
rm -rf qemu-${QEMU_VERSION}
tar Jxf qemu-${QEMU_VERSION}.tar.xz
}
do_build_qemu()
{
echo "building..."
pushd qemu-${QEMU_VERSION}
make all
popd
}
do_install_qemu()
{
echo "installing..."
pushd qemu-${QEMU_VERSION}
sudo make install
popd
}
do_build_qemu()
{
do_extract_qemu
do_configure
do_build_qemu
do_install_qemu
}
do_extract_gdb()
{
echo "extracting GDB..."
rm -rf gdb-${GDB_VERSION}
tar Jxf gdb-${GDB_VERSION}.tar.xz
}
do_build_gdb()
{
do_extract_gdb
rm -rf gdb
mkdir gdb
pushd gdb
../gdb-${GDB_VERSION}/configure --enable-tui --prefix=/opt/gdb-${GDB_VERSION}-x86_64-none-elf --target=x86_64-none-elf --program-prefix=x86_64-none-elf-
make all install
popd
}
# main
do_install_prerequisites
do_get_qemu
do_build_qemu
do_get_gdb
do_build_gdb
The resulting new paths for QEMU and GDB after installation would be:
/opt/qemu-5.0.0/bin/qemu-system-x86_64
/opt/gdb-9.2-x86_64-none-elf/bin/x86_64-none-elf-gdb