Re: Minimal GCC version for QEMU (was: Re: [PULL 27/49] meson: Add -Wformat-overflow=2)

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Mar 10, 2026 at 04:17:47PM +0100, Thomas Huth wrote:
> On 10/03/2026 15.51, Peter Maydell wrote:
> > On Tue, 10 Mar 2026 at 13:47, Fabiano Rosas <farosas@suse.de> wrote:
> > > This gives me:
> > > 
> > > ../tests/qtest/ast2700-sgpio-test.c: In function ‘test_output_pins’:
> > > ../tests/qtest/ast2700-sgpio-test.c:27:33: error: ‘sprintf’ may write a
> > > terminating nul past the end of the destination
> > > [-Werror=format-overflow=]
> > > 
> > > ../tests/qtest/ast2700-sgpio-test.c: In function ‘test_irq_level_high’:
> > > ../tests/qtest/ast2700-sgpio-test.c:85:33: error: ‘sprintf’ may write a
> > > terminating nul past the end of the destination
> > > [-Werror=format-overflow=]
> > > 
> > > ../tests/qtest/arm-cpu-features.c: In function ‘test_query_cpu_model_expansion_kvm’:
> > > ../tests/qtest/arm-cpu-features.c:578:35: error: ‘%u’ directive writing
> > > between 1 and 10 bytes into a region of size 5
> > > [-Werror=format-overflow=]
> > > 
> > > ../configure
> > > --target-list=x86_64-softmmu,i386-softmmu,aarch64-softmmu,arm-softmmu,ppc64-softmmu,s390x-softmmu,riscv64-softmmu,aarch64-linux-user,loongarch64-softmmu
> > > --disable-plugins --enable-modules --enable-werror
> > > --enable-trace-backends=log,dtrace --enable-debug --enable-docs
> > > --enable-rust --enable-strict-rust-lints
> > > 
> > > gcc version 7.5.0 (SUSE Linux)
> > 
> > This is quite an old GCC, so it's probably less good at noticing
> > when there might be an overflow and when not (or it has bugs
> > that have been fixed in subsequent versions).
> 
> By the way, I think we likely could bump the minimum GCC version to a newer
> level nowadays. GCC 7.4 was chosen for NetBSD 9 at that point in time:
> 
>  https://gitlab.com/qemu-project/qemu/-/issues/614
>  https://gitlab.com/qemu-project/qemu/-/commit/3830df5f83b9b52d949676
> 
> ... but since NetBSD 10 has been released since a while, we could likely
> bump the minimum GCC version to 10.4 now, see:
> 
>  https://cvsweb.netbsd.org/bsdweb.cgi/src/doc/3RDPARTY?rev=1.1905.2.14;content-type=text%2Fplain;only_with_tag=netbsd-10-0-RELEASE
> 
> WDYT?

Yep, if any distro needing 7.4 is out of our support matrix we can
bump it. Likewise clang can probably be bumped too.


With regards,
Daniel
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