Bug#1072004: linux: regression in the 9p protocol in 6.8 breaks autopkgtest qemu jobs (affecting debci)

[Emanuele Rocca <ema@debian.org>]

Hello Thorsten,

On 2024-05-27 02:31, Thorsten Leemhuis wrote:
> Would also help a lot to know if this is a 6.8.y only thing, or happens
> with 6.9 and mainline as well, as 6.8.y will likely be EOLed soon.

I could reproduce the issue with 6.9.2 too, will try mainline tomorrow.

FTR the procedure is quite simple. To build a sid qemu testbed:

 autopkgtest-build-qemu unstable /tmp/sid.img

Run the autopkgtest:

 autopkgtest -ddd -B dpdk -- autopkgtest-virt-qemu --debug --show-boot /tmp/sid.img

After a while the test hangs with:

 autopkgtest-virt-qemu: DBG: executing copydown /tmp/alog/tests-tree/ /tmp/autopkgtest.uG6tsJ/build.6QA/src/
 [...]
 autopkgtest-virt-qemu: DBG:  +>?

Then one can build a new kernel with:

 make oldconfig
 scripts/config --disable DEBUG_INFO
 scripts/config --disable DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
 make -j`nproc` bindeb-pkg

Boot the QCOW image:

 qemu-system-x86_64 -cpu host -machine accel=kvm -drive file=sid.img,format=qcow2 -m 4G -smp `nproc`

Upgrade the kernel, and run the autopkgtest again as above.

  Emanuele