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From: Jonathan Wakely <redi@gcc.gnu.org>
To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org
Subject: [gcc r11-5447] libstdc++: Fix some more deadlocks in tests [PR 97936]
Date: Thu, 26 Nov 2020 16:25:00 +0000 (GMT) [thread overview]
Message-ID: <20201126162500.84644396EC63@sourceware.org> (raw)
https://gcc.gnu.org/g:10522ed1089277e2aa6cd708205aa5c730179cf0
commit r11-5447-g10522ed1089277e2aa6cd708205aa5c730179cf0
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Nov 26 12:55:47 2020 +0000
libstdc++: Fix some more deadlocks in tests [PR 97936]
The missed notifications fixed in r11-5383 also happen in some other
tests which have similar code.
libstdc++-v3/ChangeLog:
PR libstdc++/97936
* testsuite/29_atomics/atomic/wait_notify/bool.cc: Fix missed
notifications by making the new thread wait until the parent
thread is waiting on the condition variable.
* testsuite/29_atomics/atomic/wait_notify/pointers.cc: Likewise.
* testsuite/29_atomics/atomic_flag/wait_notify/1.cc: Likewise.
* testsuite/29_atomics/atomic_ref/wait_notify.cc: Likewise.
Diff:
---
libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc | 6 +++++-
libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/pointers.cc | 6 +++++-
libstdc++-v3/testsuite/29_atomics/atomic_flag/wait_notify/1.cc | 6 +++++-
libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc | 6 +++++-
4 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc
index c14a2391d68..1fc01491173 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/bool.cc
@@ -36,11 +36,16 @@ main ()
std::mutex m;
std::condition_variable cv;
+ std::unique_lock<std::mutex> l(m);
std::atomic<bool> a(false);
std::atomic<bool> b(false);
std::thread t([&]
{
+ {
+ // This ensures we block until cv.wait(l) starts.
+ std::lock_guard<std::mutex> ll(m);
+ }
cv.notify_one();
a.wait(false);
if (a.load())
@@ -48,7 +53,6 @@ main ()
b.store(true);
}
});
- std::unique_lock<std::mutex> l(m);
cv.wait(l);
std::this_thread::sleep_for(100ms);
a.store(true);
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/pointers.cc b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/pointers.cc
index 87830236e0e..3b699e9133b 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/pointers.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/pointers.cc
@@ -36,6 +36,7 @@ main ()
std::mutex m;
std::condition_variable cv;
+ std::unique_lock<std::mutex> l(m);
long aa;
long bb;
@@ -43,12 +44,15 @@ main ()
std::atomic<long*> a(nullptr);
std::thread t([&]
{
+ {
+ // This ensures we block until cv.wait(l) starts.
+ std::lock_guard<std::mutex> ll(m);
+ }
cv.notify_one();
a.wait(nullptr);
if (a.load() == &aa)
a.store(&bb);
});
- std::unique_lock<std::mutex> l(m);
cv.wait(l);
std::this_thread::sleep_for(100ms);
a.store(&aa);
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_flag/wait_notify/1.cc b/libstdc++-v3/testsuite/29_atomics/atomic_flag/wait_notify/1.cc
index 991713fbcde..5d5e06dde31 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_flag/wait_notify/1.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_flag/wait_notify/1.cc
@@ -36,18 +36,22 @@ main()
std::mutex m;
std::condition_variable cv;
+ std::unique_lock<std::mutex> l(m);
std::atomic_flag a;
std::atomic_flag b;
std::thread t([&]
{
+ {
+ // This ensures we block until cv.wait(l) starts.
+ std::lock_guard<std::mutex> ll(m);
+ }
cv.notify_one();
a.wait(false);
b.test_and_set();
b.notify_one();
});
- std::unique_lock<std::mutex> l(m);
cv.wait(l);
std::this_thread::sleep_for(100ms);
a.test_and_set();
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc b/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc
index b38fc206d46..bc5a7d0d8bf 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc
@@ -37,17 +37,21 @@ Tp check_wait_notify(Tp val1, Tp val2)
std::mutex m;
std::condition_variable cv;
+ std::unique_lock<std::mutex> l(m);
Tp aa = val1;
std::atomic_ref<Tp> a(aa);
std::thread t([&]
{
+ {
+ // This ensures we block until cv.wait(l) starts.
+ std::lock_guard<std::mutex> ll(m);
+ }
cv.notify_one();
a.wait(val1);
if (a.load() != val2)
a = val1;
});
- std::unique_lock<std::mutex> l(m);
cv.wait(l);
std::this_thread::sleep_for(100ms);
a.store(val2);
reply other threads:[~2020-11-26 16:25 UTC|newest]
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