I've installed the impish kernel 5.13.0-32 on top of jammy; zfs module loads fine:
$ uname -r 5.13.0-32-generic $ modinfo zfs | grep filename: filename: /lib/modules/5.13.0-32-generic/updates/dkms/zfs.ko $ strings /lib/modules/5.13.0-32-generic/updates/dkms/zfs.ko|grep -e vermagic= -e GCC -e ^version=|sort -u GCC: (Ubuntu 11.2.0-13ubuntu1) 11.2.0 vermagic=5.13.0-32-generic SMP mod_unload modversions version=2.0.6-1ubuntu3 ** Tags removed: verification-needed-impish ** Tags added: verification-done-impish -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1954676 Title: jammy 5.15 kernel soft lockup when zfs.ko is loaded on s390x w/ gcc >= 11.2.0-10ubuntu1 / gcc-11 PLT regression on s390x Status in Ubuntu on IBM z Systems: Fix Committed Status in gcc-11 package in Ubuntu: Fix Released Status in linux package in Ubuntu: Fix Committed Status in gcc-11 source package in Impish: New Status in linux source package in Impish: Fix Committed Status in gcc-11 source package in Jammy: Fix Released Status in linux source package in Jammy: Fix Committed Bug description: [Impact] Installing zfs-dkms seems to trigger a soft lockup issue as soon as zfs.ko is loaded. When the soft lockup happens the system isn't reachable anymore via ssh and on the console we can see some exlicit rcu stall warnings. This seems to happen only when zfs is compile with gcc >= 11.2.0-10ubuntu1. Downgrading gcc to previous versions doesn't show the problem and zfs is working just fine. [Test case] On s390x install the latest 5.15 Jammy kernel and run: apt install zfs-dkms [Fix] Temporary workaround is to build zfs with gcc-10 on s390x. [Regression potential] Building a kernel module with a different compiler is never 100% safe, we may experience potential crashes / panics if the ABI is not compatible. Moreover, if we build zfs with gcc-10 we are going to lose some of the performance benefits provided by gcc-11. However these regressions are limited to zfs on s390x and without this change zfs is broken anyway on this architecture. [Further analysis] @IBM Issue report to zfs upstream at https://github.com/openzfs/zfs/issues/12942 Reverting https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=2335aa8771acd06b082d3e15d9f21ae0a802afd7 appears to make everything work, the compiled kernel and zfs.ko are loadable/unloadable once again. Please bring this issue to the attention of Ilya Leoshkevich Potentially this means we may have missbuilt userspace binaries in the archive for s390x. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1954676/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
