------- Comment From [email protected] 2020-01-13 03:43 EDT------- IBM Bugzilla status -> closed Fix Released with all requested distros
-- 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/1854059 Title: [UBUNTU] kernel: cpu idle time calculation Status in Ubuntu on IBM z Systems: Fix Released Status in linux package in Ubuntu: Fix Released Status in linux source package in Bionic: Fix Released Status in linux source package in Disco: Fix Released Status in linux source package in Eoan: Fix Released Bug description: Description: kernel: cpu idle time calculation Symptom: The cpu idle time reported within /proc/stat as well as in /sys/devices/system/cpu/cpuX/idle_time_us sometimes may show incorrect values. Problem: The kernel tries to figure out when a cpu entered idle by accessing its per-cpu data structure. There is an ordering problem: if a remote cpu has an idle_enter value which is not zero, and an idle_exit value which is zero, it is assumed it is idle since "now". The "now" timestamp however is taken before the idle_enter value is read. This in turn means that "now" can be smaller than idle_enter of the remote cpu. Unconditionally subtracting idle_enter from "now" can thus lead to a negative value (aka large unsigned value). Solution: Move the get_tod_clock() invocation. Upstream-ID: https://github.com/torvalds/linux/commit/3d7efa4edd07be5c5c3ffa95ba63e97e070e1f3f Patch tagged as "stable". Tracking the integration of this patch in the relevant distros.. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1854059/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
