Tag Archives: kernel

A story of Docker, QEMU, and memfd_create()

Last year I stumbled across a problem with the execution of a Docker container in a CI environment. The interesting case was that this is a container for a foreign architecture, which is supported by the --platform option and there are even official images on Docker Hub for this.

Initially, the problem presented itself like this:

$ docker run -it --rm --platform linux/arm64 [...] arm64v8/ubuntu:jammy
root@d6fb5c478cb6:/# ps
Error, do this: mount -t proc proc /proc

This means the ps(1) command could not run in this Docker container. At first I trusted the error message and thought that /proc might really not be mounted. However, that is usually taken care of by Docker and this following check confirmed that it is in fact mounted:

root@d6fb5c478cb6:/# mount | grep proc | head -n1
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)

Well, now what is actually the problem here with running a Docker container for a foreign architecture?

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Hauppauge WinTV HVR-1300 with Linux kernel 2.6.38

After the upgrade to Linux kernel 2.6.38, the boot process for my machine hang quite long while Populating /dev with existing devices through uevents. After investigations it turns out that the cx88 driver used for my Hauppauge WinTV HVR-1300 tv card was not correctly converted to the new mutex system while removing the BKL. This is being tracked in the kernel bugzilla as bug #31962.

Fortunately, there is a patch attached to the mentioned bug report which resolves the problem:

cd /usr/src/linux
wget -O cx88-2.6.38-fix-driver-deadlocks.patch 'https://bugzilla.kernel.org/attachment.cgi?id=53722'
patch -p1 < cx88-2.6.38-fix-driver-deadlocks.patch

[Edited on 2011-04-23: replaced patch 52902 with 53722]

After applying the patch, build and install your kernel as usual. But there are still some more problems with 2.6.38 related to tvtime. See also my next post.

I do not follow kernel development close enough to know in which git tree this has to show up to confirm if it has been merged yet. Hopefully this patch will make it into the next kernel release.