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Date: Fri, 26 May 2017 05:28:04 +0000 (UTC)
From: "John Zhuge (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
Message-ID: <JIRA.13073233.1495137082000.299870.1495776484139@Atlassian.JIRA>
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Subject: [jira] [Commented] (HDFS-11851) getGlobalJNIEnv() may deadlock if
 exception is thrown
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archived-at: Fri, 26 May 2017 05:28:09 -0000


    [ https://issues.apache.org/jira/browse/HDFS-11851?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16025830#comment-16025830 ] 

John Zhuge commented on HDFS-11851:
-----------------------------------

Thanks for adding the unit test.

Discovered the patch didn't compile on Mac because Mac has {{PTHREAD_RECURSIVE_MUTEX_INITIALIZER}} but not {{PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP}}. If we'd like to support Mac, there may be 2 choices:

1) #ifdef
{code}
diff --git a/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/os/posix/mutexes.c b/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/os/posix/mutexes.c
index c4c2f262135..a4e0e46d4a9 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/os/posix/mutexes.c
+++ b/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/os/posix/mutexes.c
@@ -22,7 +22,11 @@
 #include <stdio.h>

 mutex hdfsHashMutex = PTHREAD_MUTEX_INITIALIZER;
-mutex jvmMutex = PTHREAD_MUTEX_INITIALIZER;
+#if defined __APPLE__ && defined __MACH__
+mutex jvmMutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER;
+#else
+mutex jvmMutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
+#endif

 int mutexLock(mutex *m) {
   int ret = pthread_mutex_lock(m);
{code}

2) Use {{pthread_mutexattr_settype(&mta, PTHREAD_MUTEX_RECURSIVE);}} but this means we need to add a static initializer.

> getGlobalJNIEnv() may deadlock if exception is thrown
> -----------------------------------------------------
>
>                 Key: HDFS-11851
>                 URL: https://issues.apache.org/jira/browse/HDFS-11851
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: libhdfs
>    Affects Versions: 3.0.0-alpha3
>            Reporter: Henry Robinson
>            Assignee: Sailesh Mukil
>            Priority: Blocker
>         Attachments: HDFS-11851.000.patch, HDFS-11851.001.patch, HDFS-11851.002.patch
>
>
> HDFS-11529 introduced a deadlock into {{getGlobalJNIEnv()}} if an exception is thrown. {{getGlobalJNIEnv()}} holds {{jvmMutex}}, but {{printExceptionAndFree()}} will eventually try to acquire that lock in {{setTLSExceptionStrings()}}.
> The exception might get caught from {{loadFileSystems}}:
> {code}
> jthr = invokeMethod(env, NULL, STATIC, NULL,
>                          "org/apache/hadoop/fs/FileSystem",
>                          "loadFileSystems", "()V");
>         if (jthr) {
>             printExceptionAndFree(env, jthr, PRINT_EXC_ALL, "loadFileSystems");
>         }
>     }
> {code}
> and here's the relevant parts of the stack trace from where I call this API in Impala, which uses {{libhdfs}}:
> {code}
> #0  __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
> #1  0x00007ffff4a8d657 in _L_lock_909 () from /lib/x86_64-linux-gnu/libpthread.so.0
> #2  0x00007ffff4a8d480 in __GI___pthread_mutex_lock (mutex=0x47ce960 <jvmMutex>) at ../nptl/pthread_mutex_lock.c:79
> #3  0x0000000002f06056 in mutexLock (m=<optimized out>) at /data/2/jenkins/workspace/impala-hadoop-dependency/hadoop/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/os/posix/mutexes.c:28
> #4  0x0000000002efe817 in setTLSExceptionStrings (rootCause=0x0, stackTrace=0x0) at /data/2/jenkins/workspace/impala-hadoop-dependency/hadoop/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/jni_helper.c:581
> #5  0x0000000002f065d7 in printExceptionAndFreeV (env=0x513c1e8, exc=0x508a8c0, noPrintFlags=<optimized out>, fmt=0x34349cf "loadFileSystems", ap=0x7fffffffb660)
>     at /data/2/jenkins/workspace/impala-hadoop-dependency/hadoop/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/exception.c:183
> #6  0x0000000002f0683d in printExceptionAndFree (env=<optimized out>, exc=<optimized out>, noPrintFlags=<optimized out>, fmt=<optimized out>)
>     at /data/2/jenkins/workspace/impala-hadoop-dependency/hadoop/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/exception.c:213
> #7  0x0000000002eff60f in getGlobalJNIEnv () at /data/2/jenkins/workspace/impala-hadoop-dependency/hadoop/hadoop-hdfs-project/hadoop-hdfs/src/main/native/libhdfs/jni_helper.c:463
> {code}


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