Bug 1485900

Summary: Robust mutex may deadlock (fixed upstream)
Product: [Fedora] Fedora Reporter: Petr Špaček <pspacek>
Component: glibcAssignee: Florian Weimer <fweimer>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact: Florian Weimer <fweimer>
Priority: unspecified    
Version: 26CC: aoliva, arjun, codonell, dj, fweimer, jakub, law, mfabian, pfrankli, rth, siddhesh
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: glibc-2.25-10.fc26 glibc-2.25.90-30.fc27 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-09-02 22:24:44 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 Petr Špaček 2017-08-28 12:00:16 UTC 
Description of problem:
Glibc 2.25 has a bug in pthread_mutex_lock which may lead to deadlock.
This is alredy fixed upstream, see
https://sourceware.org/bugzilla/show_bug.cgi?id=21778

Version-Release number of selected component (if applicable):
glibc 2.25

How reproducible: 100 %

Steps to Reproduce:
1. install Knot Resolver (knot-resolver)
2. run the resolver with multiple processes sharing single cache (kresd parameter -f 2)
3. put the resolver under heavy load (e.g. using resperf tool)

Actual results:
Resolver deadlocks within a minute or two.

Expected results:
It should not deadlock.

Additional info:
We have verified that the problem does not appear on Glibc 2.26. GDB shows deadlock on the right spot pointing towards https://sourceware.org/bugzilla/show_bug.cgi?id=21778 .
Comment 1 Florian Weimer 2017-08-28 12:41:00 UTC 
I'm going to backport the upstream fixes into the upstream stable branch and import that into Fedora.
Comment 2 Petr Špaček 2017-08-28 13:02:23 UTC 
Awesome, thank you!
Comment 3 Florian Weimer 2017-08-29 08:15:45 UTC 
Bodhi update: https://bodhi.fedoraproject.org/updates/FEDORA-2017-103e80de0b

(Somehow, it didn't make it to the bug so far.)
Comment 4 Fedora Update System 2017-09-01 11:53:17 UTC 
glibc-2.25-10.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-103e80de0b
Comment 5 Fedora Update System 2017-09-02 22:24:44 UTC 
glibc-2.25-10.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.