Public bug reported: Hi,
I'm reproducing a kernel bug in vmalloc_sync_all() with a 32-bit x86 kernel. The problem appears in Linux ubuntu 4.15.0-50-generic #54-Ubuntu SMP Mon May 6 18:45:45 UTC 2019 i686 i686 i686 GNU/Linux Kernels 4.15.0-49 and prior work fine. The kernel 4.18.0-20-generic works fine. This problem has not been experienced with upstream Linux kernels. It appears that invoking vmalloc_sync_all() a few times end up triggering this issue. This can be triggered by restarting the lttng- sessiond service with lttng-modules-dkms installed (sometimes a few restarts are needed to trigger the bug). This ends up unloading and reloading those modules, which issues a few vmalloc_sync_all() as side- effect. I'm not reporting this issue with the "ubuntu-bug linux" command because it crashes the system on that kernel (system hangs, no console output). My test system runs within a kvm virtual machine on a 64-bit host. lsb release: Description: Ubuntu 18.04.2 LTS Release: 18.04 Information about my kernel: linux-image-4.15.0-50-generic: Installed: 4.15.0-50.54 Candidate: 4.15.0-50.54 Version table: *** 4.15.0-50.54 500 500 http://ca.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages 500 http://security.ubuntu.com/ubuntu bionic-security/main i386 Packages 100 /var/lib/dpkg/status Information about lttng-modules-dkms: lttng-modules-dkms: Installed: 2.10.5-1ubuntu1.2 Candidate: 2.10.5-1ubuntu1.2 Version table: *** 2.10.5-1ubuntu1.2 500 500 http://ca.archive.ubuntu.com/ubuntu bionic-updates/universe i386 Packages 100 /var/lib/dpkg/status 2.10.5-1ubuntu1 500 500 http://ca.archive.ubuntu.com/ubuntu bionic/universe i386 Packages ** Affects: linux (Ubuntu) Importance: Undecided Status: Confirmed ** Tags: bionic ** Attachment added: "kernel BUG screenshot" https://bugs.launchpad.net/bugs/1830433/+attachment/5266352/+files/Screenshot_ubuntu-bionic-32bit_2019-05-23_10%3A20%3A08.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1830433 Title: 32-bit x86 kernel 4.15.0-50 crash in vmalloc_sync_all To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1830433/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs