[
https://issues.apache.org/jira/browse/KUDU-3119?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17155078#comment-17155078
]
Alexey Serbin commented on KUDU-3119:
-------------------------------------
One more instance of TSAN race report, log is attached.
[^kudu-tool-test.20200709.txt.xz]
I guess there is real race if trying to add a block at the same index from two
different threads. Yes, there is a lock per index, but consider what happens
when two threads trying to access using {{operator[]}} if an element at the
index which was not present:
{noformat}
bool LogBlockManager::AddLogBlock(LogBlockRefPtr lb) {
// InsertIfNotPresent doesn't use move semantics, so instead we just
// insert an empty scoped_refptr and assign into it down below rather
// than using the utility function.
int index = lb->block_id().id() & kBlockMapMask;
std::lock_guard<simple_spinlock> l(*managed_block_shards_[index].lock);
auto& blocks_by_block_id = *managed_block_shards_[index].blocks_by_block_id;
LogBlockRefPtr* entry_ptr = &blocks_by_block_id[lb->block_id()];
if (*entry_ptr) {
// Already have an entry for this block ID.
return false;
}
...
{noformat}
> ToolTest.TestFsAddRemoveDataDirEndToEnd reports race under TSAN
> ---------------------------------------------------------------
>
> Key: KUDU-3119
> URL: https://issues.apache.org/jira/browse/KUDU-3119
> Project: Kudu
> Issue Type: Bug
> Components: CLI, test
> Reporter: Alexey Serbin
> Priority: Minor
> Attachments: kudu-tool-test.20200709.txt.xz, kudu-tool-test.log.xz
>
>
> Sometimes the {{TestFsAddRemoveDataDirEndToEnd}} scenario of the {{ToolTest}}
> reports races for TSAN builds:
> {noformat}
> /data0/somelongdirectorytoavoidrpathissues/src/kudu/src/kudu/tools/kudu-tool-test.cc:266:
> Failure
> Failed
> Bad status: Runtime error: /tmp/dist-test-taskIZqSmU/build/tsan/bin/kudu:
> process exited with non-ze
> ro status 66
> Google Test trace:
> /data0/somelongdirectorytoavoidrpathissues/src/kudu/src/kudu/tools/kudu-tool-test.cc:265:
> W0506 17:5
> 6:02.744191 4432 flags.cc:404] Enabled unsafe flag: --never_fsync=true
> I0506 17:56:02.780252 4432 fs_manager.cc:263] Metadata directory not provided
> I0506 17:56:02.780442 4432 fs_manager.cc:269] Using write-ahead log
> directory (fs_wal_dir) as metad
> ata directory
> I0506 17:56:02.789638 4432 fs_manager.cc:399] Time spent opening directory
> manager: real 0.007s
> user 0.005s sys 0.002s
> I0506 17:56:02.789986 4432 env_posix.cc:1676] Not raising this process' open
> files per process limi
> t of 1048576; it is already as high as it can go
> I0506 17:56:02.790426 4432 file_cache.cc:465] Constructed file cache lbm
> with capacity 419430
> ==================
> WARNING: ThreadSanitizer: data race (pid=4432)
> ...
> {noformat}
> The log is attached.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
