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Bug 1878268

Summary: librbd QoS throttling might result in an assertion failure
Product: [Red Hat Storage] Red Hat Ceph Storage Reporter: Jason Dillaman <jdillama>
Component: RBDAssignee: Jason Dillaman <jdillama>
Status: CLOSED ERRATA QA Contact: Gopi <gpatta>
Severity: medium Docs Contact: Ranjini M N <rmandyam>
Priority: unspecified    
Version: 4.2CC: asakthiv, ceph-eng-bugs, gpatta, rmandyam, tserlin
Target Milestone: ---   
Target Release: 4.2   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: ceph-14.2.11-22.el8cp, ceph-14.2.11-22.el7cp Doc Type: Bug Fix
Doc Text:
.Applications using librbd works when client-side QoS throttling is enabled Previously, when client-side QoS throttling was enabled in librbd, it could crash because the data path was not properly protected with a lock. With this release, the missing lock is added and the applications using librbd for IO works as expected when client-side QoS throttling is enabled.
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-01-12 14:57:11 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:    
Bug Blocks: 1890121    

Description Jason Dillaman 2020-09-11 18:18:41 UTC
Description of problem:
A race condition is possible between IO being throttled and the throttle completing that can lead to a crash in librbd clients.

Version-Release number of selected component (if applicable):
4.0

How reproducible:
Race condition

Steps to Reproduce:
1. enable QoS throttles on an RBD image
2. perform intensive IO to trigger the throttles

Actual results:
 ceph version 14.2.9 (581f22da52345dba46ee232b73b990f06029a2a0) nautilus (stable)
 1: (ceph::__ceph_assert_fail(char const*, char const*, int, char const*)+0x14a) [0x7f9955cf0875]
 2: (()+0x253a3d) [0x7f9955cf0a3d]
 3: (()+0x2127e1) [0x7f995f1fe7e1]
 4: (()+0xc654c) [0x7f995f0b254c]
 5: (()+0xab539) [0x7f995f097539]
 6: (TokenBucketThrottle::add_tokens()+0xdc) [0x7f9955dbad8c]
 7: (TokenBucketThrottle::schedule_timer()+0xb3) [0x7f9955dbaea3]
 8: (FunctionContext::finish(int)+0x2c) [0x7f9955dbf11c]
 9: (Context::complete(int)+0x9) [0x7f9955d6fd89]
 10: (SafeTimer::timer_thread()+0x180) [0x7f9955dc1bf0]
 11: (SafeTimerThread::entry()+0xd) [0x7f9955dc345d]
 12: (()+0x7e25) [0x7f99541d7e25]
 13: (clone()+0x6d) [0x7f9952a7d34d]

     0> 2020-08-07 07:19:22.172 7f99357fb700 -1 *** Caught signal (Aborted) **
 in thread 7f99357fb700 thread_name:safe_timer

Expected results:
librbd does not throw an assertion

Additional info:

Comment 1 RHEL Program Management 2020-09-11 18:18:48 UTC
Please specify the severity of this bug. Severity is defined here:
https://bugzilla.redhat.com/page.cgi?id=fields.html#bug_severity.

Comment 10 errata-xmlrpc 2021-01-12 14:57:11 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 (Important: Red Hat Ceph Storage 4.2 Security and Bug Fix update), 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-2021:0081