Re: Bug with Windows tap network when running qemu-system-ppc with Mac OS 9 guest

[Bin Meng]

Hi Howard,

On Fri, Mar 26, 2021 at 2:40 PM Howard Spoelstra <hsp.cat7@gmail.com> wrote:
>
> On Fri, Mar 26, 2021 at 2:50 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> >
> > Hi Howard,
> >
> > On Fri, Mar 26, 2021 at 1:35 AM Peter Maydell <peter.maydell@linaro.org> 
> > wrote:
> > >
> > > (adding the relevant people to the cc list)
> > >
> > > On Thu, 25 Mar 2021 at 17:26, Howard Spoelstra <hsp.cat7@gmail.com> wrote:
> > > >
> > > > Hi,
> > > >
> > > > When running qemu-system-ppc with Mac OS guest, the guest crashes when
> > > > using a tap network connection. Openvpn 2.4.9-I601-win10 is installed
> > > > with TAP-Windows 9.24.2. A tap connection called TapQemu is bridged
> > > > with the default ethernet connection. It gets activated when I start
> > > > qemu.
> > > >
> > > > To reproduce, compile qemu-system-ppc from current source and run:
> > > >
> > > > qemu-system-ppc.exe ^
> > > > -L pc-bios ^
> > > > -M mac99 ^
> > > > -m 128 ^
> > > > -sdl -serial stdio ^
> > > > -boot c ^
> > > > -drive file=C:\Mac-disks\9.2.img,format=raw,media=disk ^
> > > > -device sungem,netdev=network01 -netdev tap,ifname=TapQemu,id=network01
> > > >
> > > > I bisected to the commit below. Thanks for looking into this.
> >
> > Thanks for reporting.
> >
> > Can you please provide some further information:
> >
> > 1. Does "-net user" work on Windows?
> > 2. If running QEMU under Linux, does "-net tap" or "-net user" work?
> >
> > Regards,
> > Bin
>
> Hello Bin,
>
> Thanks for getting back to me. I forgot to mention that reverting the
> above patch restores functionality. And that other applications using
> the same tap device work correctly.
> In answer to your questions:
>
> 1. Yes, slirp works on Windows 10 with this setup.
> 2. Yes, in Linux both tap and slirp work.

Thanks! Just to be clear, the above testing was performed with commit
969e50b61a285b0cc8dea6d4d2ade3f758d5ecc7, right?

>
> My Windows build is done with a fully up to date msys2 installation.
>
> I tried to debug in Windows:
> (gdb) run
> Starting program: c:\qemu-master-msys2\qemu-system-ppc.exe -L pc-bios
> -M mac99 -m 128 -sdl -serial stdio -boot c -drive
> "file=C:\Mac-disks\9.2-usb-pci-ddk.img,format=raw,media=disk" -device
> "sungem,netdev=network01" -netdev "tap,ifname=TapQemu,id=network01" -S
> [New Thread 13304.0x1f00]
> [New Thread 13304.0x2f84]
> [New Thread 13304.0x3524]
> [New Thread 13304.0x2b8c]
> [New Thread 13304.0x368c]
> [New Thread 13304.0x3668]
> [New Thread 13304.0xf4c]
> [New Thread 13304.0x49c]
> [New Thread 13304.0x1d4c]
> [New Thread 13304.0x7fc]
> [Thread 13304.0x7fc exited with code 0]
> [New Thread 13304.0x357c]
> [New Thread 13304.0x7c0]
> [New Thread 13304.0x3564]
> [New Thread 13304.0x26f4]
> [New Thread 13304.0x2f68]
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffb9edea991 in ?? () from c:\qemu-master-msys2\libglib-2.0-0.dll
> (gdb) bt
> #0  0x00007ffb9edea991 in ?? () from c:\qemu-master-msys2\libglib-2.0-0.dll
> #1  0x000800000480bf50 in ?? ()
> Backtrace stopped: previous frame inner to this frame (corrupt stack?)
> (gdb)
>
> Even before I could attach to the process.

Is QEMU crashed, or the MacOS guest crashed?

Regards,
Bin