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Posted to commits@kudu.apache.org by al...@apache.org on 2020/12/09 07:23:39 UTC
[kudu] branch master updated: [client] make metacache reset safe
This is an automated email from the ASF dual-hosted git repository.
alexey pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/kudu.git
The following commit(s) were added to refs/heads/master by this push:
new ae45cd1 [client] make metacache reset safe
ae45cd1 is described below
commit ae45cd15c2703e3cfaf62aabb20ba79b961b3135
Author: Alexey Serbin <al...@apache.org>
AuthorDate: Tue Dec 8 20:33:21 2020 -0800
[client] make metacache reset safe
I noticed that the newly added TxnManagerTest.BeginManyTransactions
test scenario started failing with ASAN heap-use-after-free warnings.
After looking a that, it turned out that the original code was assuming
the cache wouldn't be ever reset before calling the MetaCache's
destructor. However, changelist 232474a51 introduced a new method
MetaCache::ClearCache() and since then the method is being called upon
altering a table if the partitioning scheme has been updated.
This patch resolves the issue by introducing so-called tablet server
registry that's never reset indeed, where entries in the tablet server
cache are just references to the entries in the registry (they are
raw pointers, actually).
The newly added test scenario was reliably producing AddressSanitizer's
heap-use-after-free warnings every time I ran it using ASAN build.
Below is a snapshot of the relevant traces captured when running the
new test scenario without the changes in the client metacache.
AddressSanitizer: heap-use-after-free on address 0x608000129e20 at pc 0x00000078bd54 bp 0x7fa731d0b240 sp 0x7fa731d0b238
READ of size 4 at 0x608000129e20 thread T149 (rpc reactor-146)
#0 0x78bd53 in base::subtle::NoBarrier_Load(int const volatile*) src/kudu/gutil/atomicops-internals-x86.h:200:10
#1 0x7fa79520e227 in base::SpinLock::SpinLoop(long, int*) src/kudu/gutil/spinlock.cc:86:10
#2 0x7fa79520e38b in base::SpinLock::SlowLock() src/kudu/gutil/spinlock.cc:104:25
#3 0x7fa7a099aab0 in std::unique_lock<kudu::simple_spinlock>::lock() ../../../include/c++/8/bits/std_mutex.h:267:17
#4 0x7fa7a0991e3e in std::unique_lock<kudu::simple_spinlock>::unique_lock(kudu::simple_spinlock&) ../../../include/c++/8/bits/std_mutex.h:197:2
#5 0x7fa7a0abfda1 in kudu::client::internal::RemoteTabletServer::InitProxy(kudu::client::KuduClient*, std::function<void (kudu::Status const&)> const&) src/kudu/client/meta_cache.cc:145:39
#6 0x7fa7a0ac60f5 in kudu::client::internal::MetaCacheServerPicker::PickLeader(std::function<void (kudu::Status const&, kudu::client::internal::RemoteTabletServer*)> const&, kudu::MonoTime const&) src/kudu/client/meta_cache.cc:524:11
#7 0x7fa7a09b2dcf in kudu::rpc::RetriableRpc<kudu::client::internal::RemoteTabletServer, kudu::tserver::WriteRequestPB, kudu::tserver::WriteResponsePB>::SendRpc() src/kudu/rpc/retriable_rpc.h:163:19
#8 0x7fa7a09ac6cc in kudu::client::internal::Batcher::FlushBuffer(kudu::client::internal::RemoteTablet*, std::vector<kudu::client::internal::InFlightOp*, std::allocator<kudu::client::internal::InFlightOp*> > const&) src/kudu/client/batcher.cc:911:8
#9 0x7fa7a09a9e38 in kudu::client::internal::Batcher::FlushBuffersIfReady() src/kudu/client/batcher.cc:884:5
#10 0x7fa7a09abd2d in kudu::client::internal::Batcher::TabletLookupFinished(kudu::client::internal::InFlightOp*, kudu::Status const&) src/kudu/client/batcher.cc:851:3
#11 0x7fa7a0acec66 in kudu::client::internal::LookupRpc::SendRpcCb(kudu::Status const&) src/kudu/client/meta_cache.cc:923:3
#12 0x7fa7a0ab8800 in kudu::client::internal::AsyncLeaderMasterRpc<kudu::master::GetTableLocationsRequestPB, kudu::master::GetTableLocationsResponsePB>::SendRpc()::'lambda'()::operator()() const src/kudu/client/master_proxy_rpc.cc:130:26
0x608000129e20 is located 0 bytes inside of 96-byte region [0x608000129e20,0x608000129e80)
freed by thread T163 here:
#0 0x65c650 in operator delete(void*) thirdparty/src/llvm-9.0.0.src/projects/compiler-rt/lib/asan/asan_new_delete.cc:160:399
#1 0x7fa7a0aec859 in void STLDeleteContainerPairSecondPointers<std::__detail::_Node_iterator<std::pair<std::string const, kudu::client::internal::RemoteTabletServer*>, false, true> >(std::__detail::_Node_iterator<std::pair<std::string const, kudu::client::internal::RemoteTabletServer*>, false, true>, std::__detail::_Node_iterator<std::pair<std::string const, kudu::client::internal::RemoteTabletServer*>, false, true>) src/kudu/gutil/stl_util.h:199:5
#2 0x7fa7a0ad96d1 in void STLDeleteValues<std::unordered_map<std::string, kudu::client::internal::RemoteTabletServer*, std::hash<std::string>, std::equal_to<std::string>, std::allocator<std::pair<std::string const, kudu::client::internal::RemoteTabletServer*> > > >(std::unordered_map<std::string, kudu::client::internal::RemoteTabletServer*, std::hash<std::string>, std::equal_to<std::string>, std::allocator<std::pair<std::string const, kudu::client::internal::RemoteTabletServer*> [...]
#3 0x7fa7a0ad4188 in kudu::client::internal::MetaCache::ClearCache() src/kudu/client/meta_cache.cc:1257:3
previously allocated by thread T149 (rpc reactor-146) here:
#0 0x65bc98 in operator new(unsigned long) thirdparty/src/llvm-9.0.0.src/projects/compiler-rt/lib/asan/asan_new_delete.cc:99:386
#1 0x7fa7a0ac7bcb in kudu::client::internal::MetaCache::UpdateTabletServerUnlocked(kudu::master::TSInfoPB const&) src/kudu/client/meta_cache.cc:596:48
#2 0x7fa7a0ad0802 in kudu::client::internal::MetaCache::ProcessGetTableLocationsResponse(kudu::client::KuduTable const*, std::string const&, bool, kudu::master::GetTableLocationsResponsePB const&, kudu::client::internal::MetaCacheEntry*, int) src/kudu/client/meta_cache.cc:1030:7
#3 0x7fa7a0acf9c0 in kudu::client::internal::MetaCache::ProcessLookupResponse(kudu::client::internal::LookupRpc const&, kudu::client::internal::MetaCacheEntry*, int) src/kudu/client/meta_cache.cc:941:10
#4 0x7fa7a0ace64e in kudu::client::internal::LookupRpc::SendRpcCb(kudu::Status const&) src/kudu/client/meta_cache.cc:911:31
#5 0x7fa7a0ab8800 in kudu::client::internal::AsyncLeaderMasterRpc<kudu::master::GetTableLocationsRequestPB, kudu::master::GetTableLocationsResponsePB>::SendRpc()::'lambda'()::operator()() const src/kudu/client/master_proxy_rpc.cc:130:26
#6 0x7fa79b2c1620 in kudu::rpc::OutboundCall::CallCallback() src/kudu/rpc/outbound_call.cc:274:5
#7 0x7fa79b2c1af0 in kudu::rpc::OutboundCall::SetResponse(std::unique_ptr<kudu::rpc::CallResponse, std::default_delete<kudu::rpc::CallResponse> >) src/kudu/rpc/outbound_call.cc:306:5
#8 0x7fa79b26ef5e in kudu::rpc::Connection::HandleCallResponse(std::unique_ptr<kudu::rpc::InboundTransfer, std::default_delete<kudu::rpc::InboundTransfer> >) src/kudu/rpc/connection.cc:735:14
#9 0x7fa79b26e0d6 in kudu::rpc::Connection::ReadHandler(ev::io&, int) src/kudu/rpc/connection.cc:673:7
SUMMARY: AddressSanitizer: heap-use-after-free src/kudu/gutil/atomicops-internals-x86.h:200:10 in base::subtle::NoBarrier_Load(int const volatile*)
Shadow bytes around the buggy address:
0x0c108001d370: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 fa
0x0c108001d380: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fd fd
0x0c108001d390: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 fa
0x0c108001d3a0: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fd fd
0x0c108001d3b0: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 fa
=>0x0c108001d3c0: fa fa fa fa[fd]fd fd fd fd fd fd fd fd fd fd fd
0x0c108001d3d0: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 fa
0x0c108001d3e0: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fd fd
0x0c108001d3f0: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 fa
0x0c108001d400: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 fa
0x0c108001d410: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 fa
Change-Id: I03ec9318526fbfc2da9b068eb3bbd9cd996efbca
Reviewed-on: http://gerrit.cloudera.org:8080/16839
Tested-by: Alexey Serbin <as...@cloudera.com>
Reviewed-by: Andrew Wong <aw...@cloudera.com>
---
src/kudu/client/client-test.cc | 29 +++++++++++++++++++++++++++++
src/kudu/client/client.h | 1 +
src/kudu/client/meta_cache.cc | 27 ++++++++++++++++++---------
src/kudu/client/meta_cache.h | 23 +++++++++++++++++------
4 files changed, 65 insertions(+), 15 deletions(-)
diff --git a/src/kudu/client/client-test.cc b/src/kudu/client/client-test.cc
index e375c92..2047d03 100644
--- a/src/kudu/client/client-test.cc
+++ b/src/kudu/client/client-test.cc
@@ -125,6 +125,7 @@
#include "kudu/util/random_util.h"
#include "kudu/util/semaphore.h"
#include "kudu/util/slice.h"
+#include "kudu/util/scoped_cleanup.h"
#include "kudu/util/status.h"
#include "kudu/util/stopwatch.h"
#include "kudu/util/test_macros.h"
@@ -2248,6 +2249,34 @@ TEST_F(ClientTest, TestMetaCacheExpiry) {
ASSERT_FALSE(entry.stale());
}
+// This test scenario verifies that reset of the metacache is safe while working
+// with the client. The scenario calls MetaCache::ClearCache() in a rather
+// synthetic way, but the natural control flow does something similar to that
+// when alterting a table by adding a new range partition (see
+// KuduTableAlterer::Alter() for details).
+TEST_F(ClientTest, ClearCacheAndConcurrentWorkload) {
+ CountDownLatch latch(1);
+ thread cache_cleaner([&]() {
+ const auto sleep_interval = MonoDelta::FromMilliseconds(3);
+ while (!latch.WaitFor(sleep_interval)) {
+ client_->data_->meta_cache_->ClearCache();
+ }
+ });
+ auto thread_joiner = MakeScopedCleanup([&] {
+ latch.CountDown();
+ cache_cleaner.join();
+ });
+
+ constexpr const int kLowIdx = 0;
+ constexpr const int kHighIdx = 1000;
+ const auto runUntil = MonoTime::Now() + MonoDelta::FromSeconds(1);
+ while (MonoTime::Now() < runUntil) {
+ NO_FATALS(InsertTestRows(client_table_.get(), kHighIdx, kLowIdx));
+ NO_FATALS(UpdateTestRows(client_table_.get(), kLowIdx, kHighIdx));
+ NO_FATALS(DeleteTestRows(client_table_.get(), kLowIdx, kHighIdx));
+ }
+}
+
TEST_F(ClientTest, TestBasicIdBasedLookup) {
auto tablet_ids = cluster_->mini_tablet_server(0)->ListTablets();
ASSERT_FALSE(tablet_ids.empty());
diff --git a/src/kudu/client/client.h b/src/kudu/client/client.h
index c0f93cc..8b8557a 100644
--- a/src/kudu/client/client.h
+++ b/src/kudu/client/client.h
@@ -808,6 +808,7 @@ class KUDU_EXPORT KuduClient : public sp::enable_shared_from_this<KuduClient> {
friend class tools::RemoteKsckCluster;
FRIEND_TEST(kudu::ClientStressTest, TestUniqueClientIds);
+ FRIEND_TEST(ClientTest, ClearCacheAndConcurrentWorkload);
FRIEND_TEST(ClientTest, ConnectionNegotiationTimeout);
FRIEND_TEST(ClientTest, TestBasicIdBasedLookup);
FRIEND_TEST(ClientTest, TestCacheAuthzTokens);
diff --git a/src/kudu/client/meta_cache.cc b/src/kudu/client/meta_cache.cc
index d7fc94f..adc2989 100644
--- a/src/kudu/client/meta_cache.cc
+++ b/src/kudu/client/meta_cache.cc
@@ -41,7 +41,6 @@
#include "kudu/gutil/basictypes.h"
#include "kudu/gutil/map-util.h"
#include "kudu/gutil/port.h"
-#include "kudu/gutil/stl_util.h"
#include "kudu/gutil/strings/substitute.h"
#include "kudu/master/master.pb.h"
#include "kudu/master/master.proxy.h"
@@ -580,20 +579,30 @@ MetaCache::MetaCache(KuduClient* client,
replica_visibility_(replica_visibility) {
}
-MetaCache::~MetaCache() {
- STLDeleteValues(&ts_cache_);
-}
-
void MetaCache::UpdateTabletServerUnlocked(const TSInfoPB& pb) {
DCHECK(lock_.is_write_locked());
- RemoteTabletServer* ts = FindPtrOrNull(ts_cache_, pb.permanent_uuid());
+ const auto& ts_uuid = pb.permanent_uuid();
+ auto* ts = FindPtrOrNull(ts_cache_, ts_uuid);
if (ts) {
ts->Update(pb);
return;
}
- VLOG(1) << "Client caching new TabletServer " << pb.permanent_uuid();
- InsertOrDie(&ts_cache_, pb.permanent_uuid(), new RemoteTabletServer(pb));
+ // First check whether the information about the tablet server is already
+ // present in the registry.
+ ts = FindPointeeOrNull(ts_registry_, ts_uuid);
+ if (ts) {
+ // If the tablet server is already registered, update the existing entry.
+ ts->Update(pb);
+ } else {
+ // If the tablet server isn't registered, add a new entry.
+ unique_ptr<RemoteTabletServer> entry(new RemoteTabletServer(pb));
+ ts = entry.get();
+ EmplaceOrDie(&ts_registry_, ts_uuid, std::move(entry));
+ }
+ // Now add the entry into the cache.
+ VLOG(1) << Substitute("client caching new TabletServer $0", ts_uuid);
+ InsertOrDie(&ts_cache_, ts_uuid, ts);
}
// A (tablet id) --> tablet lookup. May be in-flight to a master, or may be
@@ -1254,7 +1263,7 @@ void MetaCache::ClearNonCoveredRangeEntries(const std::string& table_id) {
void MetaCache::ClearCache() {
VLOG(3) << "Clearing cache";
std::lock_guard<percpu_rwlock> l(lock_);
- STLDeleteValues(&ts_cache_);
+ ts_cache_.clear();
tablets_by_id_.clear();
tablets_by_table_and_key_.clear();
entry_by_tablet_id_.clear();
diff --git a/src/kudu/client/meta_cache.h b/src/kudu/client/meta_cache.h
index af59d2e..2b21e94 100644
--- a/src/kudu/client/meta_cache.h
+++ b/src/kudu/client/meta_cache.h
@@ -146,6 +146,8 @@ struct RemoteReplica {
bool failed;
};
+typedef std::unordered_map<std::string, std::unique_ptr<RemoteTabletServer>>
+ TabletServerRegistry;
typedef std::unordered_map<std::string, RemoteTabletServer*> TabletServerMap;
// A ServerPicker for tablets servers, backed by the MetaCache.
@@ -373,7 +375,6 @@ class MetaCacheEntry {
}
private:
-
// The expiration time of this cached entry.
MonoTime expiration_time_;
@@ -395,7 +396,7 @@ class MetaCache : public RefCountedThreadSafe<MetaCache> {
public:
// The passed 'client' object must remain valid as long as MetaCache is alive.
MetaCache(KuduClient* client, ReplicaController::Visibility replica_visibility);
- ~MetaCache();
+ ~MetaCache() = default;
// Determines what type of operation a MetaCache lookup is being done for.
enum class LookupType {
@@ -529,11 +530,21 @@ class MetaCache : public RefCountedThreadSafe<MetaCache> {
percpu_rwlock lock_;
- // Cache of Tablet Server locations: TS UUID -> RemoteTabletServer*.
+ // Registry of all tablet servers as a map of tablet server's
+ // UUID -> std::unique_ptr<RemoteTabletServer>.
+ //
+ // Given that the set of tablet servers in a cluster is bounded by physical
+ // machines and every tablet server has its unique identifier, we never remove
+ // entries from this map until the MetaCache is destructed. Note that the
+ // ClearCache() method doesn't touch this registry, but updates ts_cache_ map
+ // below which contains raw pointers to the elements in this registry.
+ // So, there is no need to use shared_ptr and alike for the entries.
//
- // Given that the set of tablet servers is bounded by physical machines, we never
- // evict entries from this map until the MetaCache is destructed. So, no need to use
- // shared_ptr, etc.
+ // Protected by lock_.
+ TabletServerRegistry ts_registry_;
+
+ // Cache of Tablet Server locations: TS UUID -> RemoteTabletServer*.
+ // The cache can be cleared by the ClearCache() method.
//
// Protected by lock_.
TabletServerMap ts_cache_;