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* [Bug libstdc++/53830] New: condition_variable_any - deadlock issue
@ 2012-07-02 16:21 m_reicha at informatik dot uni-kl.de
2012-07-02 16:54 ` [Bug libstdc++/53830] " redi at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: m_reicha at informatik dot uni-kl.de @ 2012-07-02 16:21 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53830
Bug #: 53830
Summary: condition_variable_any - deadlock issue
Classification: Unclassified
Product: gcc
Version: 4.6.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: m_reicha@informatik.uni-kl.de
Created attachment 27730
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27730
Simple test program that causes deadlock
I believe there is a bug (or a pitfall at least) in std::condition_variable_any
that can cause deadlocks. Actually, one of my programs just froze because of
this.
I am using gcc 4.6.3. However, I believe the bug is also in the latest headers
in the CVS (trunk).
A common use case for condition_variables, is something like this:
std::mutex mutex;
std::condition_variable_any cv;
// called by thread#1: waits for data from another thread
void wait_for_data()
{
std::unique_lock<std::mutex> lock(mutex);
cv.wait_for(lock, std::chrono::seconds(2)); // no predicate for simplicity
// dequeue data
}
// called by thread#2: passes data to waiting thread
void provide_data()
{
std::unique_lock<std::mutex> lock(mutex);
// enqueue data
cv.notify_one();
}
If thread#1's timeout expires while thread#2 already holds the lock on "mutex",
this will deadlock.
This is because condition_variable_any uses another internal mutex, which is
usually acquired after "mutex". However, if the timeout expires, the internal
mutex is acquired before "mutex".
By adding a nonsense "sleep_for", we can actually make a simple test program
always deadlocks (see attachment).
Notably, the same test program does not deadlock, if a
boost::condition_variable_any or a std::condition_variable is used instead of a
std::condition_variable_any.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/53830] condition_variable_any - deadlock issue
2012-07-02 16:21 [Bug libstdc++/53830] New: condition_variable_any - deadlock issue m_reicha at informatik dot uni-kl.de
@ 2012-07-02 16:54 ` redi at gcc dot gnu.org
2012-07-02 17:25 ` redi at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-02 16:54 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53830
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-07-02
Target Milestone|--- |4.6.4
Ever Confirmed|0 |1
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-02 16:53:47 UTC ---
confirmed
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/53830] condition_variable_any - deadlock issue
2012-07-02 16:21 [Bug libstdc++/53830] New: condition_variable_any - deadlock issue m_reicha at informatik dot uni-kl.de
2012-07-02 16:54 ` [Bug libstdc++/53830] " redi at gcc dot gnu.org
@ 2012-07-02 17:25 ` redi at gcc dot gnu.org
2012-07-04 22:17 ` redi at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-02 17:25 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53830
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
AssignedTo|unassigned at gcc dot |redi at gcc dot gnu.org
|gnu.org |
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-02 17:25:16 UTC ---
similar issue to PR 50862, I should have fixed it at the same time
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/53830] condition_variable_any - deadlock issue
2012-07-02 16:21 [Bug libstdc++/53830] New: condition_variable_any - deadlock issue m_reicha at informatik dot uni-kl.de
2012-07-02 16:54 ` [Bug libstdc++/53830] " redi at gcc dot gnu.org
2012-07-02 17:25 ` redi at gcc dot gnu.org
@ 2012-07-04 22:17 ` redi at gcc dot gnu.org
2012-07-05 0:19 ` redi at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-04 22:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53830
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-04 22:17:24 UTC ---
Author: redi
Date: Wed Jul 4 22:17:18 2012
New Revision: 189268
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=189268
Log:
PR libstdc++/53830
* include/std/condition_variable (condition_variable_any::wait):
Move _Unlock type to class scope.
(condition_variable_any::wait_until): Reuse it.
* testsuite/30_threads/condition_variable_any/53830.cc: New.
Added:
trunk/libstdc++-v3/testsuite/30_threads/condition_variable_any/53830.cc
Modified:
trunk/libstdc++-v3/ChangeLog
trunk/libstdc++-v3/include/std/condition_variable
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/53830] condition_variable_any - deadlock issue
2012-07-02 16:21 [Bug libstdc++/53830] New: condition_variable_any - deadlock issue m_reicha at informatik dot uni-kl.de
` (2 preceding siblings ...)
2012-07-04 22:17 ` redi at gcc dot gnu.org
@ 2012-07-05 0:19 ` redi at gcc dot gnu.org
2012-07-05 1:10 ` redi at gcc dot gnu.org
2012-07-05 1:16 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-05 0:19 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53830
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-05 00:19:41 UTC ---
Author: redi
Date: Thu Jul 5 00:19:36 2012
New Revision: 189273
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=189273
Log:
PR libstdc++/53830
* include/std/condition_variable (condition_variable_any::wait):
Move _Unlock type to class scope.
(condition_variable_any::wait_until): Reuse it.
* testsuite/30_threads/condition_variable_any/53830.cc: New.
Added:
branches/gcc-4_7-branch/libstdc++-v3/testsuite/30_threads/condition_variable_any/53830.cc
Modified:
branches/gcc-4_7-branch/libstdc++-v3/ChangeLog
branches/gcc-4_7-branch/libstdc++-v3/include/std/condition_variable
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/53830] condition_variable_any - deadlock issue
2012-07-02 16:21 [Bug libstdc++/53830] New: condition_variable_any - deadlock issue m_reicha at informatik dot uni-kl.de
` (3 preceding siblings ...)
2012-07-05 0:19 ` redi at gcc dot gnu.org
@ 2012-07-05 1:10 ` redi at gcc dot gnu.org
2012-07-05 1:16 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-05 1:10 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53830
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-05 01:10:18 UTC ---
Author: redi
Date: Thu Jul 5 01:10:10 2012
New Revision: 189275
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=189275
Log:
PR libstdc++/53830
* include/std/condition_variable (condition_variable_any::wait):
Move _Unlock type to class scope.
(condition_variable_any::wait_until): Reuse it.
* testsuite/30_threads/condition_variable_any/53830.cc: New.
Added:
branches/gcc-4_6-branch/libstdc++-v3/testsuite/30_threads/condition_variable_any/53830.cc
Modified:
branches/gcc-4_6-branch/libstdc++-v3/ChangeLog
branches/gcc-4_6-branch/libstdc++-v3/include/std/condition_variable
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/53830] condition_variable_any - deadlock issue
2012-07-02 16:21 [Bug libstdc++/53830] New: condition_variable_any - deadlock issue m_reicha at informatik dot uni-kl.de
` (4 preceding siblings ...)
2012-07-05 1:10 ` redi at gcc dot gnu.org
@ 2012-07-05 1:16 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: redi at gcc dot gnu.org @ 2012-07-05 1:16 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53830
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Known to fail| |4.6.3, 4.7.1
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-05 01:16:28 UTC ---
Fixed for 4.6.4, 4.7.2 and 4.8.0
^ permalink raw reply [flat|nested] 7+ messages in thread
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2012-07-02 16:21 [Bug libstdc++/53830] New: condition_variable_any - deadlock issue m_reicha at informatik dot uni-kl.de
2012-07-02 16:54 ` [Bug libstdc++/53830] " redi at gcc dot gnu.org
2012-07-02 17:25 ` redi at gcc dot gnu.org
2012-07-04 22:17 ` redi at gcc dot gnu.org
2012-07-05 0:19 ` redi at gcc dot gnu.org
2012-07-05 1:10 ` redi at gcc dot gnu.org
2012-07-05 1:16 ` redi at gcc dot gnu.org
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