Bug 1824802

Summary:	Rare assertion failure about waiters.
Product:	Red Hat Enterprise Linux 8	Reporter:	Sweet Tea Dorminy <sweettea>
Component:	kmod-kvdo	Assignee:	Sweet Tea Dorminy <sweettea>
Status:	CLOSED ERRATA	QA Contact:	Filip Suba <fsuba>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	8.1	CC:	awalsh, corwin, fsuba
Target Milestone:	rc
Target Release:	8.0
Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:	6.2.3.91	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-11-04 02:01:47 UTC	Type:	Bug
Regression:	---	Mount Type:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Sweet Tea Dorminy 2020-04-16 13:16:23 UTC

Description of problem:
In certain rare circumstances in either async mode, there can be an assertion failure from the VDO recovery journal from it attempting to double-enqueue a block for writing. This requires IO to be in progress and the journal to have no space; the journal attempts never to get more than halfway full, so being full is unlikely.

Version-Release number of selected component (if applicable):
6.2.2.109

How reproducible:
Exceedingly rare. Not observed except in unit tests.

Steps to Reproduce:
1. Unknown.

Actual results:
In userspace imitation in a unit test:
waitQueue.c:19: handleAssertionFailure: Assertion `(waiter->next_waiter == ((void *)0))' failed.
==7808== 
==7808== Process terminating with default action of signal 6 (SIGABRT): dumping core
==7808==    at 0x4B0957F: raise (in /usr/lib64/libc-2.28.so)
==7808==    by 0x4AF3894: abort (in /usr/lib64/libc-2.28.so)
==7808==    by 0x4AF3768: __assert_fail_base.cold.0 (in /usr/lib64/libc-2.28.so)
==7808==    by 0x4B01A25: __assert_fail (in /usr/lib64/libc-2.28.so)
==7808==    by 0x48BB74A: handleAssertionFailure (permassertLinuxUser.c:83)
==7808==    by 0x48B530C: assertionFailed (permassert.c:24)
==7808==    by 0x489F94D: enqueue_waiter (waitQueue.c:18)
==7808==    by 0x488B028: schedule_block_write (recoveryJournal.c:845)
==7808==    by 0x488B028: complete_write (recoveryJournal.c:1110)

The kernel assertion would look similar.

Expected results:
No assertion.

Additional info:
This bug was introduced in fixing 1657301

Comment 3 Filip Suba 2020-08-21 07:42:12 UTC

Verified SanityOnly. Regression testing passed.

Comment 6 errata-xmlrpc 2020-11-04 02:01:47 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 (kmod-kvdo bug fix and enhancement 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/RHBA-2020:4551