Bug 1618466

Summary: RT system hang due to wrong of rq's nr_running [MRG-RT]
Product: Red Hat Enterprise MRG Reporter: Beth Uptagrafft <bhu>
Component: realtime-kernelAssignee: Clark Williams <williams>
Status: CLOSED ERRATA QA Contact: Jiri Kastner <jkastner>
Severity: urgent Docs Contact: Marie Hornickova <mdolezel>
Priority: high    
Version: 2.5CC: bhu, crwood, dhoward, jiang.biao2, jkastner, lgoncalv, mkolaja, tian.yongjiang
Target Milestone: ---Keywords: ZStream
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: 3.10.0-693.38.1.rt56.628.el6rt 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 20:21:47 UTC Type: Bug
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    
Bug Blocks: 1541534, 1617941    

Comment 2 Clark Williams 2018-08-27 18:14:08 UTC
Added to MRG kernel build:

kernel-rt-3.10.0-693.38.1.rt56.628.el6rt

Brew URL:

https://brewweb.engineering.redhat.com/brew/buildinfo?buildID=757691

Comment 9 errata-xmlrpc 2018-09-25 20:21:47 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-2018:2789