Public bug reported: Endless cycle was detected few times during ubuntu 16.04 testing insied openvz VMs dmesg output and crash dump ivestigation shows that foolowing ubuntu 16.04.patch is guilty commit d6572202d986a84feda4cf7e6ce0bebaa18cb8fe Author: Colin Ian King <colin.k...@canonical.com> Date: Fri May 12 15:51:56 2017 +0100 UBUNTU:SAUCE: exec: ensure file system accounting in check_unsafe_exec is correct BugLink: http://bugs.launchpad.net/bugs/1672819
fs/exec.c:: check_unsafe_exec() ... recheck: fs_recheck = false; t = p; n_fs = 1; spin_lock(&p->fs->lock); rcu_read_lock(); while_each_thread(p, t) { if (t->fs == p->fs) n_fs++; if (t->flags & (PF_EXITING | PF_FORKNOEXEC)) fs_recheck = true; } rcu_read_unlock(); if (p->fs->users > n_fs) { if (fs_recheck) { spin_unlock(&p->fs->lock); goto recheck; <<<<<< cycles forever } bprm->unsafe |= LSM_UNSAFE_SHARE; } else p->fs->in_exec = 1; spin_unlock(&p->fs->lock); dmesg example is attached, let me know if you want to look at crash dump image. Bug is xenial-specific (4.4 kernel), other kernel branches seems are not affected. ** Affects: linux (Ubuntu) Importance: Undecided Status: Incomplete ** Tags: xenial ** Attachment added: "dmesg output" https://bugs.launchpad.net/bugs/1876856/+attachment/5366596/+files/dmesg.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1876856 Title: xenial: soft lockup in check_unsafe_exec() To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1876856/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs