kexec failure in local qemu tests

The test integration/qemu-provision.sh fails when I run it locally. Last lines in qemu.log are:

stboot: 2025/03/18 09:23:34 [DEBUG] Boot image:
 LinuxImage(
  Name: 
  Kernel: *bytes.Reader
  Initrd: *bytes.Reader
  Cmdline: console=ttyS0,115200n8
  DTB: <nil>
)
stboot: 2025/03/18 09:23:34 [INFO] Loading boot image into memory
stboot: 2025/03/18 09:23:34 [INFO] Handing over control - kexec
[    1.255949] kexec_core: Starting new kernel

(this is the kexec for the provisioning OS package). I've also seen this succeed once, and then next kexec hanged in a similar way. I.e., after reboot, attempting to boot the provisioned eample OS package.

Repro instructions: git switch --detach v0.5.2 (latest release version), rm -rf integration/cache/ (to rule out problems with stale files), ./integration/qemu-provision.sh.

The qemu version I have installed is qemu-system-x86 1:8.2.1+ds-1~bpo12+1 (from debian testing, slightly old since updating requires updating half of my system to testing).