Bug 1512587 – data race in std::promise/std::future (reported by ThreadSanitizer)

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Bug 1512587 - data race in std::promise/std::future (reported by ThreadSanitizer)

Summary:	data race in std::promise/std::future (reported by ThreadSanitizer)

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Developer Toolset
Classification:	Red Hat
Component:	gcc (Show other bugs)
Sub Component:
Version:	DTS 6.0 RHEL 6
Hardware:	All Linux

Priority	unspecified Severity medium
Target Milestone:	alpha
Target Release:	7.1
Assigned To:	Marek Polacek
QA Contact:	Michael Petlan
Docs Contact:	Vladimír Slávik

URL:
Whiteboard:
Keywords:

Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2017-11-13 10:26 EST by Paulo Andrade
Modified:	2018-05-03 01:14 EDT (History)
CC List:	8 users (show)

See Also:
Fixed In Version:	devtoolset-7-gcc-7.2.1-6.el6
Doc Type:	Bug Fix
Doc Text:	Previously, the code for the `std::promise` and `std::future` C++ standard library class templates contained a data race. The code has been fixed and the race condition no longer exists.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2018-05-03 01:13:47 EDT
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
racy2.C (454 bytes, text/plain) 2017-11-13 10:26 EST, Paulo Andrade	no flags	Details
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2018:1293	None	None	None	2018-05-03 01:14 EDT

Groups: None (edit)

Description Paulo Andrade 2017-11-13 10:26:53 EST

Created attachment 1351594 [details]
racy2.C

There should be no race (likely a false positive), but libtsan reports
a race.

  Example:

$ scl enable devtoolset-6 bash
$ g++ -fsanitize=thread -static-libtsan -g -o racy racy2.C -lpthread
$ ./racy

  Expected results would be empty output, but actual output
is a report about a race:

[...]
SUMMARY: ThreadSanitizer: data race /opt/rh/devtoolset-6/root/usr/include/c++/6.3.1/bits/unique_ptr.h:308 in std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter>::get() const

  The issue also happens in rhel7.

Comment 2 Marek Polacek 2017-12-05 08:51:30 EST

I could reproduce this with DTS 6, but DTS 7 looks fine:

# g++ --version
g++ (GCC) 7.2.1 20170829 (Red Hat 7.2.1-1)
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# g++ -fsanitize=thread -static-libtsan -g -o racy racy.C -lpthread
# ./racy
#

So we should include this BZ in DTS 7.1.

Comment 5 Michael Petlan 2018-04-26 08:07:34 EDT

Successfully reproduced with DTS-6, verified for devtoolset-7-libtsan-devel-7.3.1-5.4.
No races are reported.
VERIFIED.

Comment 8 errata-xmlrpc 2018-05-03 01:13:47 EDT

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/RHBA-2018:1293

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