MB-20760: Fix data race on VBucket::chkFlushTimeout

daverigby · daverigby · commit 2f227193d98b · 2016-11-02T16:27:08.000Z
As identified by ThreadSantizer: WARNING: ThreadSanitizer: data race (pid=23560) Write of size 8 at 0x7ff76a2e7e50 by thread T52 (mutexes: write M64345, write M85935): #0 VBucket::adjustCheckpointFlushTimeout(unsigned long) ep-engine/src/vbucket.cc:393 (ep.so+0x00000016c806) #1 VBucket::notifyOnPersistence(EventuallyPersistentEngine&, unsigned long, bool) ep-engine/src/vbucket.cc:332 (ep.so+0x00000016c806) #2 EventuallyPersistentStore::flushVBucket(unsigned short) ep-engine/src/ep.cc:3475 (ep.so+0x0000000be736) #3 Flusher::flushVB() ep-engine/src/flusher.cc:284 (ep.so+0x0000001100d1) #4 Flusher::step(GlobalTask*) ep-engine/src/flusher.cc:183 (ep.so+0x0000001110b7) #5 FlusherTask::run() ep-engine/src/tasks.cc:138 (ep.so+0x000000156642) #6 ExecutorThread::run() ep-engine/src/executorthread.cc:115 (ep.so+0x000000108d96) #7 launch_executor_thread ep-engine/src/executorthread.cc:33 (ep.so+0x000000109675) #8 CouchbaseThread::run() platform/src/cb_pthreads.cc:54 (libplatform.so.0.1.0+0x0000000057a5) #9 platform_thread_wrap platform/src/cb_pthreads.cc:66 (libplatform.so.0.1.0+0x0000000057a5) Previous read of size 8 at 0x7ff76a2e7e50 by thread T9 (mutexes: write M295): #0 VBucket::getCheckpointFlushTimeout() ep-engine/src/vbucket.cc:406 (ep.so+0x0000001683e6) #1 EventuallyPersistentEngine::doEngineStats(void const*, void (*)(char const*, unsigned short, char const*, unsigned int, void const*)) ep-engine/src/ep_engine.cc:3628 (ep.so+0x0000000e9678) #2 EventuallyPersistentEngine::getStats(void const*, char const*, int, void (*)(char const*, unsigned short, char const*, unsigned int, void const*)) ep-engine/src/ep_engine.cc:4680 (ep.so+0x0000000ea930) #3 EvpGetStats ep-engine/src/ep_engine.cc:235 (ep.so+0x0000000eb9fe) #4 stat_executor memcached/daemon/mcbp_executors.cc:3367 (memcached+0x00000046c94b) #5 process_bin_packet memcached/daemon/mcbp_executors.cc:4650 (memcached+0x00000046481d) #6 mcbp_complete_nread(McbpConnection*) memcached/daemon/mcbp_executors.cc:4759 (memcached+0x00000046481d) #7 conn_nread(McbpConnection*) memcached/daemon/statemachine_mcbp.cc:314 (memcached+0x000000472678) #8 McbpStateMachine::execute(McbpConnection&) memcached/daemon/statemachine_mcbp.h:43 (memcached+0x000000447054) #9 McbpConnection::runStateMachinery() memcached/daemon/connection_mcbp.cc:1003 (memcached+0x000000447054) #10 McbpConnection::runEventLoop(short) memcached/daemon/connection_mcbp.cc:1274 (memcached+0x0000004470dd) #11 run_event_loop memcached/daemon/connections.cc:147 (memcached+0x00000044b9e9) #12 event_handler(int, short, void*) memcached/daemon/memcached.cc:851 (memcached+0x00000041466c) #13 event_persist_closure /home/couchbase/serverjenkins/workspace/cbdeps-platform-build/deps/packages/build/libevent/libevent-prefix/src/libevent/event.c:1319 (libevent_core-2.0.so.5+0x00000000b6b7) #14 event_process_active_single_queue /home/couchbase/serverjenkins/workspace/cbdeps-platform-build/deps/packages/build/libevent/libevent-prefix/src/libevent/event.c:1363 (libevent_core-2.0.so.5+0x00000000b6b7) #15 event_process_active /home/couchbase/serverjenkins/workspace/cbdeps-platform-build/deps/packages/build/libevent/libevent-prefix/src/libevent/event.c:1438 (libevent_core-2.0.so.5+0x00000000b6b7) #16 event_base_loop /home/couchbase/serverjenkins/workspace/cbdeps-platform-build/deps/packages/build/libevent/libevent-prefix/src/libevent/event.c:1639 (libevent_core-2.0.so.5+0x00000000b6b7) #17 CouchbaseThread::run() platform/src/cb_pthreads.cc:54 (libplatform.so.0.1.0+0x0000000057a5) #18 platform_thread_wrap platform/src/cb_pthreads.cc:66 (libplatform.so.0.1.0+0x0000000057a5) Location is global 'VBucket::chkFlushTimeout' of size 8 at 0x7ff76a2e7e50 (ep.so+0x000000431e50) Change-Id: I2d6f928b8a5552cf08a91c6134ad5134810966c2 Reviewed-on: http://review.couchbase.org/69234 Reviewed-by: Trond Norbye <trond.norbye@gmail.com> Tested-by: buildbot <build@couchbase.com>
diff --git a/src/vbucket.cc b/src/vbucket.cc
@@ -107,7 +107,7 @@ std::ostream& operator <<(std::ostream &out, const VBucketFilter &filter)
     return out;
 }
 
-size_t VBucket::chkFlushTimeout = MIN_CHK_FLUSH_TIMEOUT;
+std::atomic<size_t> VBucket::chkFlushTimeout(MIN_CHK_FLUSH_TIMEOUT);
 
 const vbucket_state_t VBucket::ACTIVE =
                      static_cast<vbucket_state_t>(htonl(vbucket_state_active));
diff --git a/src/vbucket.h b/src/vbucket.h
@@ -566,7 +566,7 @@ class VBucket : public RCValue {
     // The persistence checkpoint ID for this vbucket.
     AtomicValue<uint64_t> persistenceCheckpointId;
 
-    static size_t chkFlushTimeout;
+    static std::atomic<size_t> chkFlushTimeout;
 
     DISALLOW_COPY_AND_ASSIGN(VBucket);
 };

Original file line number	Diff line number	Diff line change
`@@ -107,7 +107,7 @@ std::ostream& operator <<(std::ostream &out, const VBucketFilter &filter)`
`107`	`107`	`return out;`
`108`	`108`	`}`
`109`	`109`
`110`		`-size_t VBucket::chkFlushTimeout = MIN_CHK_FLUSH_TIMEOUT;`
	`110`	`+std::atomic<size_t> VBucket::chkFlushTimeout(MIN_CHK_FLUSH_TIMEOUT);`
`111`	`111`
`112`	`112`	`const vbucket_state_t VBucket::ACTIVE =`
`113`	`113`	`static_cast<vbucket_state_t>(htonl(vbucket_state_active));`