[jira] Updated: (HADOOP-7156) getpwuid_r is not thread-safe on RHEL6

["Todd Lipcon (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HADOOP-7156?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Todd Lipcon updated HADOOP-7156:
--------------------------------

    Attachment: hadoop-7156.txt

Here's a heinous workaround for this issue:

When initializing the native library, we check for the problematic nss module - if it's on the system, we're likely to run into this issue, so it adds a lock around the getpwuid_r calls.


Do people think this hack is the right approach? My other thought was to add a new boolean config flag like hadoop.nativeio.workaround.hadoop7156 or some nonsense like that, and if that flag is set, add the monitor lock.


> getpwuid_r is not thread-safe on RHEL6
> --------------------------------------
>
>                 Key: HADOOP-7156
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7156
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 0.22.0
>         Environment: RHEL 6.0 "Santiago"
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>            Priority: Critical
>             Fix For: 0.22.0
>
>         Attachments: hadoop-7156.txt
>
>
> Due to the following bug in SSSD, functions like getpwuid_r are not thread-safe in RHEL 6.0 if sssd is specified in /etc/nsswitch.conf (as it is by default):
> https://fedorahosted.org/sssd/ticket/640
> This causes many fetch failures in the case that the native libraries are available, since the SecureIO functions call getpwuid_r as part of fstat. By enabling -Xcheck:jni I get the following trace on JVM crash:
> *** glibc detected *** /mnt/toolchain/JDK6u20-64bit/bin/java: free(): invalid pointer: 0x0000003575741d23 ***
> ======= Backtrace: =========
> /lib64/libc.so.6[0x3575675676]
> /lib64/libnss_sss.so.2(_nss_sss_getpwuid_r+0x11b)[0x7fe716cb42cb]
> /lib64/libc.so.6(getpwuid_r+0xdd)[0x35756a5dfd]

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