This bug is missing log files that will aid in diagnosing the problem. >From a terminal window please run:
apport-collect 1660518 and then change the status of the bug to 'Confirmed'. If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'. This change has been made by an automated script, maintained by the Ubuntu Kernel Team. ** Changed in: linux (Ubuntu) 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/1660518 Title: "mm/huge_memory.c: respect FOLL_FORCE/FOLL_COW for thp" needs to be ported to Xenial Kernel Status in linux package in Ubuntu: Incomplete Bug description: The following changes was pulled into atleast the Ubuntu Xenail Kernel release. http://kernel.ubuntu.com/git/kernel-ppa/mirror/ubuntu-xenial.git/commit/mm?id=b56d2a75e1daae6ff6eedfb732eadf3c13df6090 From b56d2a75e1daae6ff6eedfb732eadf3c13df6090 Mon Sep 17 00:00:00 2001 From: Linus Torvalds <torva...@linux-foundation.org> Date: Mon, 17 Oct 2016 17:29:48 -0500 Subject: UBUNTU: SAUCE: mm: remove gup_flags FOLL_WRITE games from __get_user_pages() This is an ancient bug that was actually attrempted to be fixed once (badly) by me eleven years ago in commit 4ceb5db9757a ("Fix get_user_pages() race for write access") but that was then undone due to problems on s390 by commit f33ea7f404e5 ("fix get_user_pages bug"). In the meantime, the s390 situation has long been fixed, and we can once more try to fix it by checking the pte_dirty() bit properly (and do it better). Also, the VM has become more scalable, and what was a purely theoretical race back then has become easier to trigger. To fix it, we introduce a new internal FOLL_COW flag to mark the "yes, we already did a COW" rather than play racy games with FOLL_WRITE that is very fundamental, and then use the pte dirty flag to validate that the FOLL_COW flag is still valid. Reported-and-tested-by: Phil "not Paul" Oester <ker...@linuxace.com> Cc: Michal Hocko <mho...@kernel.org> Cc: Andy Lutomirski <l...@kernel.org> Cc: Kees Cook <keesc...@chromium.org> Cc: Oleg Nesterov <o...@redhat.com> Cc: Willy Tarreau <w...@1wt.eu> Acked-by: Hugh Dickins <hu...@google.com> Cc: Nick Piggin <npig...@gmail.com> Cc: Greg Thelen <gthe...@google.com> Cc: sta...@vger.kernel.org Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> CVE-2016-5195 However this change introduced a bug in the kernel memory manager, in which syscalls can end up in an infinite loop when transparent huge pages are enabled. See the following Commit: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/mm/huge_memory.c?id=8310d48b125d19fcd9521d83b8293e63eb1646aa This fix has not been ported to the Xenial kernel, and thus the infinite loop issue is hitting certain machines quite often. Example of bug hitting: http://www.mail-archive.com/lldb-dev@lists.llvm.org/msg03851.html Kernel Info: Linux Ubuntu 16.04.1 LTS (GNU/Linux 4.4.0-51-generic x86_64) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1660518/+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