------- Comment From geral...@de.ibm.com 2020-09-23 15:37 EDT------- (In reply to comment #161) > 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.
This conflict was already noticed by stable maintainer, see https://lore.kernel.org/stable/20200917155334.0965120...@mail.kernel.org/ An adjusted version of the patch was sent for v5.4 stable, see https://lore.kernel.org/stable/patch-1.thread-41918b.git-41918be365c0 .your-ad-here.call-01600439945-ext-8991@work.hours/ Therefore, our expectation is that this will now go in to v5.4 stable via the normal process. Of course, you could also take the adjusted version from the link above. Regarding the regression risk, while the patch does touch scary common memory management code, it will have absolutely no effect on other architectures than s390. This is ensured by the fact that only s390 provides / implements the new helper functions. And for s390, this actually is a critical (and carefully tested) fix for a (previous) regression, so it can hardly get any more regressive... -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to 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) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1896726/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
