Possible VM deadlock due to FileSystems.getDefault and System.loadLibrary interplay
Vitaly Davidovich
vitalyd at gmail.com
Wed Jan 3 17:13:52 UTC 2018
On Wed, Jan 3, 2018 at 12:00 PM, Alan Bateman <Alan.Bateman at oracle.com>
wrote:
> The stack trace looks like JDK 8 or older. The initialization has changed
> quite a bit in JDK 9+ and would be interesting to see if you can duplicate
> it there.
>
Yes - it's 8u152 as I mentioned in the follow-up email (sorry, should've
mentioned that initially).
Trying this on JDK9 is a bit tricky as the code (and its dependencies) in
question isn't easily runnable on 9 without quite a bit of work.
Do you agree with the deadlock assessment though? That's what it looks like
to me but wanted to make sure I'm not missing anything.
Thanks Alan
>
> -Alan
>
>
> On 03/01/2018 16:56, Vitaly Davidovich wrote:
>
>> Hi all,
>>
>> Consider the following stacktraces of the main app thread and a background
>> thread:
>>
>> "main" #1 prio=5 os_prio=0 tid=0x0000000001bfd000 nid=0x1958 waiting for
>> monitor entry [0x00002b98ceba3000]
>>
>> java.lang.Thread.State: BLOCKED (on object monitor)
>>
>> at java.lang.Runtime.loadLibrary0(Runtime.java:862)
>>
>> - waiting to lock <0x00000007bf834b20> (a
>> java.lang.Runtime)
>>
>> at java.lang.System.loadLibrary(System.java:1122)
>>
>> at sun.nio.fs.UnixNativeDispatcher$1.run(
>> UnixNativeDispatcher.java:573)
>>
>> at sun.nio.fs.UnixNativeDispatcher$1.run(
>> UnixNativeDispatcher.java:571)
>>
>> at java.security.AccessController.doPrivileged(Native
>> Method)
>>
>> at sun.nio.fs.UnixNativeDispatcher.<clinit>(
>> UnixNativeDispatcher.java:571)
>>
>> at sun.nio.fs.UnixFileSystem.<ini
>> t>(UnixFileSystem.java:67)
>>
>> at sun.nio.fs.LinuxFileSystem.<
>> init>(LinuxFileSystem.java:39)
>>
>> at sun.nio.fs.LinuxFileSystemProvider.newFileSystem(
>> LinuxFileSystemProvider.java:46)
>>
>> at sun.nio.fs.LinuxFileSystemProvider.newFileSystem(
>> LinuxFileSystemProvider.java:39)
>>
>> at sun.nio.fs.UnixFileSystemProvider.<init>(
>> UnixFileSystemProvider.java:56)
>>
>> at sun.nio.fs.LinuxFileSystemProvider.<init>
>> (LinuxFileSystemProvider.java:41)
>>
>> at
>> sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
>> Method)
>>
>> at sun.reflect.NativeConstructorA
>> ccessorImpl.newInstance(
>> NativeConstructorAccessorImpl.java:62)
>>
>> at sun.reflect.DelegatingConstructorAccessorI
>> mpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
>>
>> at java.lang.reflect.Constructor.
>> newInstance(Constructor.java:423)
>>
>> at java.lang.Class.newInstance(Class.java:442)
>>
>> at sun.nio.fs.DefaultFileSystemProvider.createProvider(
>> DefaultFileSystemProvider.java:48)
>>
>> at sun.nio.fs.DefaultFileSystemProvider.create(
>> DefaultFileSystemProvider.java:63)
>>
>> at java.nio.file.FileSystems$DefaultFileSystemHolder.
>> getDefaultProvider(FileSystems.java:108)
>>
>> at java.nio.file.FileSystems$DefaultFileSystemHolder.
>> access$000(FileSystems.java:89)
>>
>> at java.nio.file.FileSystems$Defa
>> ultFileSystemHolder$1.run(
>> FileSystems.java:98)
>>
>> at java.nio.file.FileSystems$Defa
>> ultFileSystemHolder$1.run(
>> FileSystems.java:96)
>>
>> at java.security.AccessController.doPrivileged(Native
>> Method)
>>
>> at java.nio.file.FileSystems$DefaultFileSystemHolder.
>> defaultFileSystem(FileSystems.java:96)
>>
>> at java.nio.file.FileSystems$DefaultFileSystemHolder.<
>> clinit>(FileSystems.java:90)
>>
>> at java.nio.file.FileSystems.getD
>> efault(FileSystems.java:
>> 176)
>>
>> at java.nio.file.Paths.get(Paths.java:84)
>>
>> at <some_package>.ServiceLoader.
>> setup(ServiceLoader.java:446)
>>
>> at <some_package>.MetadataAdminLoader.main(
>> MetadataAdminLoader.java:52)
>>
>>
>>
>>
>>
>> "shardDbExecutor-0-pool-0" #33 prio=5 os_prio=0 tid=0x0000000001ebf000
>> nid=0x1d01 in Object.wait() [0x00002b991f941000]
>>
>> java.lang.Thread.State: RUNNABLE
>>
>> at java.nio.file.FileSystems.getD
>> efault(FileSystems.java:
>> 176)
>>
>> at java.nio.file.Paths.get(Paths.java:138)
>>
>> at sun.misc.Launcher$ExtClassLoader.findLibrary(
>> Launcher.java:224)
>>
>> at java.lang.ClassLoader.loadLibr
>> ary(ClassLoader.java:1830)
>>
>> at java.lang.Runtime.loadLibrary0(Runtime.java:870)
>>
>> - locked <0x00000007bf834b20> (a java.lang.Runtime)
>>
>> at java.lang.System.loadLibrary(System.java:1122)
>>
>> at sun.security.ec.SunEC$1.run(SunEC.java:60)
>>
>> at sun.security.ec.SunEC$1.run(SunEC.java:58)
>>
>> at java.security.AccessController.doPrivileged(Native
>> Method)
>>
>> at sun.security.ec.SunEC.<clinit>(SunEC.java:58)
>>
>> at
>> sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
>> Method)
>>
>> at sun.reflect.NativeConstructorA
>> ccessorImpl.newInstance(
>> NativeConstructorAccessorImpl.java:62)
>>
>> at sun.reflect.DelegatingConstructorAccessorI
>> mpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
>>
>> at java.lang.reflect.Constructor.
>> newInstance(Constructor.java:423)
>>
>> at java.lang.Class.newInstance(Class.java:442)
>>
>> at sun.security.jca.ProviderConfig$2.run(
>> ProviderConfig.java:221)
>>
>> at sun.security.jca.ProviderConfig$2.run(
>>
>> ProviderConfig.java:206)
>>
>> at java.security.AccessController.doPrivileged(Native
>> Method)
>>
>> at sun.security.jca.ProviderConfig.doLoadProvider(
>> ProviderConfig.java:206)
>>
>> at sun.security.jca.ProviderConfig.getProvider(
>> ProviderConfig.java:187)
>>
>> - locked <0x00000007bea03f48> (a sun.security.jca.
>> ProviderConfig)
>>
>> at sun.security.jca.ProviderList.
>> getProvider(ProviderList.java:233)
>>
>> at sun.security.jca.ProviderList.
>> getService(ProviderList.java:331)
>>
>> at sun.security.jca.GetInstance.
>> getInstance(GetInstance.java:157)
>>
>> at javax.net.ssl.SSLContext.getIn
>> stance(SSLContext.java:156)
>>
>> at com.microsoft.sqlserver.jdbc.
>> TDSChannel.enableSSL(IOBuffer.java:1658)
>>
>> at com.microsoft.sqlserver.jdbc.SQLServerConnection.
>> connectHelper(SQLServerConnection.java:1976)
>>
>> at com.microsoft.sqlserver.jdbc.S
>> QLServerConnection.login(
>> SQLServerConnection.java:1627)
>>
>> at com.microsoft.sqlserver.jdbc.SQLServerConnection.
>> connectInternal(SQLServerConnection.java:1458)
>>
>> at com.microsoft.sqlserver.jdbc.S
>> QLServerConnection.connect(
>> SQLServerConnection.java:772)
>>
>> at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(
>> SQLServerDriver.java:1168)
>>
>> at java.sql.DriverManager.getConnection(DriverManager.
>> java:664)
>>
>> at java.sql.DriverManager.getConnection(DriverManager.
>> java:208)
>>
>> at <some_package>.ConnectionPool.createGoodConnection(
>> ConnectionPool.java:565)
>>
>> at <some_package>.ConnectionPool.createNewConnection(
>> ConnectionPool.java:519)
>>
>> at <some_package>.ConnectionPool.
>> getConnection(ConnectionPool.java:407)
>>
>> at <some_package>.StatementCachingConnectionImpl
>> .setupConnection(StatementCachingConnectionImpl.java:94)
>>
>> at <some_package>.StatementCachingConnectionImpl.<init>(
>> StatementCachingConnectionImpl.java:54)
>>
>> at <some_package>.TestConnectionFactories$
>> FaultInjectingConnection.<init>(TestConnectionFactories.java:90)
>>
>> at <some_package>.TestConnectionF
>> actories.lambda$static$3(
>> TestConnectionFactories.java:33)
>>
>> at <some_package>.TestConnectionFactories$$
>> Lambda$12/1738236591.newConnection(Unknown Source)
>>
>> at <some_package>.SedaExecutor.
>> setupConnections(SedaExecutor.java:130)
>>
>> at <some_package>.SedaExecutor$SedaThreadFactory.lambda$
>> newThread$0(SedaExecutor.java:165)
>>
>> at
>> <some_package>.SedaExecutor$SedaThreadFactory$$Lambda$22/139
>> 2419022.run(Unknown
>> Source)
>>
>> at java.lang.Thread.run(Thread.java:748)
>>
>>
>> The application intermittently hangs on startup, and the above callstacks
>> are present. It seems like there's a deadlock due to concurrent class
>> loading and default FileSystem initialization (which itself triggers class
>> loading here).
>>
>> I wasn't able to find any existing JBS entries reporting anything similar.
>> Am I seeing this right? Is this a known issue?
>>
>> Thanks
>>
>
>
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