Use QEMU v8 for emulated platforms #125
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josephleekl
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Jan 29, 2025
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------------------------------------------------------------------------------------------------------------
**Context:**
The [aarch64 wheel build CI action has been
failing](https://github.com/PennyLaneAI/pennylane-lightning/actions/workflows/wheel_linux_aarch64.yml)
since circa 24 Jan 2025. They fail with a segmentation fault during the
CIBW process. This has also been observed for similar wheel builds with
QEMU with other repositories:
docker/setup-qemu-action#188
ssciwr/clang-format-wheel#124
tonistiigi/binfmt#215
tonistiigi/binfmt#165
and fix attempt:
ssciwr/clang-format-wheel#125
It is due to using an old version (v7) of qemu that comes with binfmt.
`setup-qemu-action` by default uses `binfmt:latest` image which has not
been updated in 2 years.
**Description of the Change:**
Use a newer QEMU image (v8) from binfmt.
**Benefits:**
aarch64 wheel builds will succeed again,
[e.g.](https://github.com/PennyLaneAI/pennylane-lightning/actions/runs/13019772888?pr=1056)
**Possible Drawbacks:**
**Related GitHub Issues:**
[sc-83297]
---------
Co-authored-by: ringo-but-quantum <[email protected]>
Co-authored-by: Ali Asadi <[email protected]>
|
Hi @lkeegan, anything else you want to see here (and the other open PR)? The underlying cause of the qemu segfaults seems to be a change to the OS/kernel used by the GitHub runner VMs and qemu being built with --disable-pie which isn't happy with aslr (tonistiigi/binfmt#215 (comment)) on Ubuntu systems. Newer versions of qemu after 8.1 appear to have a patch that mitigates the issue. From the looks of it, there aren't any plans to update the tonistiigi/binfmt:latest tag to point to qemu v8 instead of v7, and setup-action-qemu doesn't seem to have plans of switching their default label to anything newer. |
|
@nightlark thanks lgtm! |
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Something has changed, potentially related to some piece of software installed on the standard GitHub Actions runner image that is causing arbitrary programs running under qemu emulation to segfault. It doesn't look like there was any update to the manylinux images for these platforms that would cause this, so the root cause is still a mystery.
Switching to using the binfmt QEMU v8 images seems to resolve the issue. Or at least using v8 makes the segfaults infrequent enough that builds are at least able to finish (builds with v7 of QEMU segfault consistently, v8 is at least able to run builds to completion and I haven't seen segfaults yet... there's just not enough data yet to say conclusively that there will never be intermittent segfaults).
Resolves #124