While working on this bug a patched kernel was created and made available here: https://people.canonical.com/~fheimes/lp1896726/ But it's a patched groovy kernel only, since the commit/patch doesn't cleanly apply to focal master-next:
git apply --stat ~/0001-mm-gup-fix-gup_fast-with-dynamic-page-table-folding.patch arch/s390/include/asm/pgtable.h | 42 ++++++++++++++++++++++++++++----------- include/linux/pgtable.h | 10 +++++++++ mm/gup.c | 18 ++++++++--------- 3 files changed, 49 insertions(+), 21 deletions(-) git apply --check ~/0001-mm-gup-fix-gup_fast-with-dynamic-page-table-folding.patch error: patch failed: arch/s390/include/asm/pgtable.h:1260 error: arch/s390/include/asm/pgtable.h: patch does not apply error: include/linux/pgtable.h: No such file or directory Please always check if a patch/commit applies cleanly to the master-next tree of the target Ubuntu kernel releases. If not double check if any further commits are needed or if a even a backport is required. There is btw. a significant regression risk associated to this patch, since it touches general memory management (page table handling and address translation) and gup code - and this includes common code, where special care taking is needed, since it may potentially affect millions of installations across all supported platforms. Hence my recommendation is to bring this in with the help of an upstream stable release update (https://www.kernel.org/doc/html/v5.4/process /stable-kernel-rules.html) to upstream kernel 5.4 - which will then be (more or less) automatically be picked up by the Canonical kernel team for focal. ** Changed in: linux (Ubuntu Groovy) Status: New => Triaged ** Changed in: linux (Ubuntu Focal) Status: New => Incomplete ** Changed in: ubuntu-z-systems Status: New => Incomplete -- 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/1896726 Title: [UBUNTU 20.04.1]Secure guest (qemu) crash during boot (mostly) but also while running workload (rare) (secure execution) Status in Ubuntu on IBM z Systems: Incomplete Status in linux package in Ubuntu: Triaged Status in linux source package in Focal: Incomplete Status in linux source package in Groovy: Triaged Bug description: Secure Execution with Ubuntu 20.04, secure guest crash during boot from time to time, crashed guest went into Shufoff state instead of Crashed state (<on_crash>preserve is set), so I can't get a dump. libvirt log file: 2020-04-21T16:35:39.382999Z qemu-system-s390x: Guest says index 19608 is available 2020-04-21 16:35:44.831+0000: shutting down, reason=crashed ---uname output--- Linux ubu204uclg1002 5.4.0-25-generic #29-Ubuntu SMP Fri Apr 17 15:05:32 UTC 2020 s390x s390x s390x GNU/Linux Machine Type = z15 8561 ---Debugger--- A debugger is not configured ---Steps to Reproduce--- I have a setup with 72 KVM guests which I can start in secure or non-secure mode. Starting all of them in secure mode back to back results in a number of guests (4..8) in Shutoff state and reason=crashed in the libvirt log. I can manually start the guest again.... no problem. Different guests are failing. Host and guests are on latest Ubuntu 20.04. The supposed fix (kernel memory management) has landed in Andrew Mortons mm tree https://lore.kernel.org/mm-commits/20200916003608.ib4ln%25a...@linux-foundation.org/T/#u Please note: while this was found with secure execution, the bug is actually present for non-KVM workloads as well. The complete patch is this: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=a338e69ba37286c0fc300ab7e6fa0227e6ca68b1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1896726/+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
