All autopkgtests for the newly accepted lvm2 (2.03.11-2.1ubuntu5) for jammy have finished running. The following regressions have been reported in tests triggered by the package:
libvirt/unknown (amd64) resource-agents/1:4.7.0-1ubuntu7.3 (amd64) Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1]. https://people.canonical.com/~ubuntu-archive/proposed- migration/jammy/update_excuses.html#lvm2 [1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions Thank you! -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lvm2 in Ubuntu. https://bugs.launchpad.net/bugs/2084233 Title: Excluded libaio library from mlock may hang system while removing rootfs snapshot Status in lvm2: Fix Released Status in lvm2 package in Ubuntu: Fix Released Status in lvm2 source package in Jammy: Fix Committed Status in lvm2 source package in Noble: Fix Committed Bug description: [ Impact ] Some LVM operations like taking or removing snapshots will cause system hangs. This can happen if parts of libaio get paged out during a snapshot operation, which will cause the underlying LVM operation to freeze completely. [ Test Plan ] This bug needs active snapshot operations to happen under memory pressure, so we've found that the following procedure consistently reproduces the issue: 1. Start fio+stress-ng stressors for IO and memory pressure. The values below will need to be tuned according to the reproducer system; the idea is to induce heavy memory pressure without triggering OOM, and without overwhelming the storage backend completely. - fio --filename=/dev/sda --direct=1 --rw=randread --bs=1M --ioengine=libaio --iodepth=256 --runtime=7200 --numjobs=4 --time_based --group_reporting --name=iops-test-job --eta-newline=1 --readonly - stress-ng --vm 2 --vm-bytes 650m --timeout 7200s 2. Repeatedly create/remove LVM snapshots - lvcreate -s -L400m -nsnap_rootfs /dev/sys1/rootfs - lvremove -f /dev/sys1/snap_rootfs Although this needs some time, we've been able to reproduce the hangs within an hour or two with the above. [ Where problems could occur ] Realistically speaking, the increased footprint of keeping libaio mlocked in memory should be fairly small. We should expect an increase in memory consumption of LVM. Under heavy memory pressure, this could reduce the performance of the system, and increase swapping. [ Other Info ] This patch has been merged as of LVM v2_03_17, so it's needed for Jammy/Noble. These two should be fairly safe, but Focal has been deliberately excluded for now until we evaluate the impact on it (as well as a patch for focal-backports). -- [ Original Description ] Hi, One of our production system hang while executing a custom backup script, using LVM snapshots and raw copies in order to build an alternative boot environment. We opened an issue on the LVM2 Github (https://github.com/lvmteam/lvm2/issues/159), and one of the contributor advises us to use at least the LVM2 2.03.17 version, built with the following patch : https://github.com/lvmteam/lvm2/commit/a3eb6ba425773224076c41aabc3c490a6a016ee6 The libaio library is, on previous versions, excluded of the mlock call and it can lead to a full system hang, specifically during a rootfs snapshot removal, as removing a shapshot freezes the underlying volume and the system won't be able to read on that volume during this operation. In rare condtions, this can be harmful if the system decides to page-out during this operation. As I understand that it may be complicated to upgrade the LVM2 version on stable releases of Ubuntu, is it possible to cherry-pick the relevant (and really simple/small) patch from the LVM2 2.03.17 version on the current LVM2 versions used by Ubuntu ? Regards, To manage notifications about this bug go to: https://bugs.launchpad.net/lvm2/+bug/2084233/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
