Hi Matthew, Thanks for helping us once again with another one of these problems. :)
This one was pretty fun to track down, and when I realized that this was a redux of the underlying problem that resize2fs also encountered, I did wonder how many libraries actually do this. So far, at least, it's just been e2fsprogs and util-linux. Appreciate you help getting the fixes shipshape and ready for integration. Thanks again, -K On Thu, Dec 05, 2024 at 03:45:30PM +1300, Matthew Ruffell wrote: > Hi Krister, > > Thanks again for tracking down another of these super subtle race > conditions. > > I have prepared debdiffs for noble, oracular and plucky. We just need to > land > the change in plucky first before we can SRU to noble. > > I have asked the Foundations Team to sponsor, hopefully the debdiff is up to > their expectations. > > Thanks, > Matthew > > On Thu, 5 Dec 2024 at 07:24, Krister Johansen <[email protected]> > wrote: > > > Hi, > > I wanted to raise awareness about a bug that my team has been running > > into on Noble. I logged a launchpad bug here with the details: > > > > https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/2090972 > > > > The short explanation is that libblkid in util-linux can misread the > > ext4 superblock checksum and incorrectly decide that it doesn't match. > > If it's systemd-udevd using libblkid to do this, then that can result in > > udev removing devlinks that it thinks don't exist any longer, even > > though the device is still present. (E.g. if libblkid doesn't find a > > filesystem, then it doesn't return the label property, and a label > > property disappearing can result in udev removing that devlink). > > > > The mount of /boot fails, because it's trying to use a > > /dev/disk/by-label path, and that path sometimes disappears because of > > the bug. This subsequently results in packaging operations and anything > > else that interacts with /boot failing. (Usually update-grub related). > > > > We've also seen the root disk have this problem, though the failure > > there was more subtle. The device mounted, but a subsequent mkinitramfs > > failed during a kernel package install, because of missing > > /dev/disk/by-label links. > > > > I've fixed the bug in libblkid and gotten the fix merged upstream. > > We've also patched this locally in our own version of util-linux. I've > > attached a patch to the bug report which is the version of the fix we > > used against the Noble packages. We haven't seen the problem reproduce > > since rolling this out. > > > > The underlying problem affects util-linux >= 2.39. Would it be possible > > for somebody to pull this patch into the affected Ubuntu util-linux > > versions? > > > > Thanks, > > > > -K > > > > -- > > Ubuntu-devel-discuss mailing list > > [email protected] > > Modify settings or unsubscribe at: > > https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss > > -- Ubuntu-devel-discuss mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
