[HADOOP-7156] getpwuid_r is not thread-safe on RHEL6

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.22.0
• Fix Version/s: 0.22.0

Environment

RHEL 6.0 "Santiago"

• Hadoop Flags: Reviewed

Release Note

Adds a new configuration hadoop.work.around.non.threadsafe.getpwuid which can be used to enable a mutex around this call to workaround thread-unsafe implementations of getpwuid_r. Users should consult http://wiki.apache.org/hadoop/KnownBrokenPwuidImplementations for a list of such systems.

• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 25/Feb/11 09:23
• Updated: 12/Dec/11 06:19
• Resolved: 11/Mar/11 18:45

Description

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]