Bug 1617941

Summary: RT system hang due to wrong of rq's nr_running [rhel-7.5.z]
Product: Red Hat Enterprise Linux 7 Reporter: Oneata Mircea Teodor <toneata>
Component: kernel-rtAssignee: Luis Claudio R. Goncalves <lgoncalv>
kernel-rt sub component: Memory Management QA Contact: Jiri Kastner <jkastner>
Status: CLOSED ERRATA Docs Contact: Marie Hornickova <mdolezel>
Severity: urgent    
Priority: high CC: bhu, crwood, dhoward, jiang.biao2, jkastner, kernel-eus-qe, lgoncalv, mkolaja, stalexan, tian.yongjiang
Version: 7.4Keywords: ZStream
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: kernel-rt-3.10.0-862.13.1.rt56.816.el7 Doc Type: Bug Fix
Doc Text:
Previously, preemption was enabled too early after a context switch. If a task was migrated to another CPU after a context switch, a mismatch between CPU and runqueue during load balancing sometimes occurred. Consequently, a runnable task on an idle CPU failed to run, and the operating system became unresponsive. This update disables preemption in the schedule_tail() function. As a result, CPU migration during post-schedule processing no longer occurs, which prevents the above mismatch. The operating system no longer hangs due to this bug.
Story Points: ---
Clone Of: 1608672 Environment:
Last Closed: 2018-09-25 19:10:41 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1608672, 1618466    
Bug Blocks:    

Description Oneata Mircea Teodor 2018-08-16 08:25:39 UTC
This bug has been copied from bug #1608672 and has been proposed to be backported to 7.5 z-stream (EUS).

Comment 8 errata-xmlrpc 2018-09-25 19:10:41 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2018:2763