Bug 1225188

Summary:	librbd: aio calls may block
Product:	Red Hat Enterprise Linux 7	Reporter:	Josh Durgin <jdurgin>
Component:	ceph-common	Assignee:	Boris Ranto <branto>
Status:	CLOSED ERRATA	QA Contact:	Warren <wusui>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	7.1	CC:	ceph-eng-bugs, ceph-qe-bugs, jdillama, jkurik, nlevine, tmuthami
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	ceph-common-0.80.7-3.el7	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:	1225171	Environment:
Last Closed:	2015-11-19 11:45:00 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:

Description Josh Durgin 2015-05-26 19:00:29 UTC

+++ This bug was initially created as a clone of Bug #1225171 +++

QEMU runs these from its threads, so blocking here causes the vcpu to lock up from the guest's perspective, resulting in messages in linux guests like

BUG: soft lockup - CPU#1 stuck for 520s!

One cause that has been observed is via Objecter-level throttling of requests:

With caching disabled, this blocks directly in aio_read/write().

With caching enabled, the cache does i/o while holding its lock, and if it is throttled in its flusher thread, for example, readx() and writex() will block waiting on the cache lock.

Comment 4 Boris Ranto 2015-06-17 18:15:56 UTC

Scratch build with the patches for the issue:

https://brewweb.devel.redhat.com/taskinfo?taskID=9379871

-> setting devel_ack+.

@Jason: This bz is for base rhel-7.2, the patches are not (can't be, yet) submitted to base rhel, moving back to ASSIGNED.

Comment 5 Boris Ranto 2015-06-17 18:17:03 UTC

*** Bug 1225189 has been marked as a duplicate of this bug. ***

Comment 7 Boris Ranto 2015-06-19 12:08:41 UTC

dist-git commits related to build ceph-common-0.80.7-3.el7:
http://pkgs.devel.redhat.com/cgit/rpms/ceph-common/commit/?h=rhel-7.2&id=4844e939f3bf9b945e3bd6713f475fcb0d12d329

Comment 10 errata-xmlrpc 2015-11-19 11:45:00 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://rhn.redhat.com/errata/RHBA-2015-2348.html