Solaris 2.6 panic when debugging with gdb

Host environment

• Operating system: macOS 10.15
• Architecture: x86-64
• QEMU flavor: qemu-system-sparc
• QEMU version: 7.0.0
• QEMU command line:

  ./qemu-system-sparc -M SS-5 -m 128 -drive file=hd.qcow2,bus=0,unit=0,media=disk -drive file=sun26gnu.iso,bus=0,unit=2,media=cdrom,readonly=on

Emulated/Virtualized environment

• Operating system: Solaris 2.6
• Architecture: SPARC

Description of problem

Running gdb with a breakpoint that gets hit triggers a panic:

non parity synchronous error ctx=fa va=ef7d97c pa=c1a47c

One time I got of the following messages as well

processor level 12 onboard interrupt not serviced
processor level 12 onboard interrupt not serviced
...

Steps to reproduce

1. Install Solaris 2.6 using https://learn.adafruit.com/build-your-own-sparc-with-qemu-and-solaris?view=all
2. Install https://archive.org/details/sun26gnu
3. Install http://download.nust.na/pub3/solaris/sunfreeware/pub/unixpackages/sparc/5.6/gdb-6.8-sol26-sparc-local.gz
4. Install http://download.nust.na/pub3/solaris/sunfreeware/pub/unixpackages/sparc/5.6/gcc-2.95.3-sol26-sparc-local.gz
5. Build a simple hello world program with debugging information

gdb ./hello
(gdb) break main
(gdb) run