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https://issues.apache.org/jira/browse/HADOOP-10442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13955576#comment-13955576
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Kihwal Lee commented on HADOOP-10442:
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[~cmccabe]: I also think the version of nslcd we used is buggy. The return
code handling before your change was just masking it, but it likely had other
side effects. I observed many lookup timeouts in NN prior to crashes, while my
own program calling the same libc functions running on the same box at the same
time had no issue. The nslcd lookup timeout was configured to be 20 seconds in
/etc/nslcd.conf.
{panel}
12:15:21,106 WARN security.Groups: Potential performance problem:
getGroups(user=xxxx) took 20020 milliseconds.
12:15:21,107 WARN security.UserGroupInformation: No groups available for user
xxxx
{panel}
bq. Also, looking at this more closely, I believe we mishandle the case where
the user is a member of no groups. This would be a pretty odd configuration (I
wonder if it's possible?).
Getting no groups after a successful getpwnam() can probably only happen when
the user was removed in between the two calls. All other cases might be
considered as errors. I saw cases of an admin user getting permission refused
for certain operations. It was fixed after the refresh command was issued. It
must have hit the no-group error when building the acl and the result was
negatively cached. If it didn't do negative caching, user-level retries would
have worked.
So, the solution might be letting the native code return 0 even on error
conditions as you suggested, but making netgroup modules not do negative
caching. That's when a valid user name has no netgroups.
> Group look-up can cause segmentation fault when certain JNI-based mapping
> module is used.
> -----------------------------------------------------------------------------------------
>
> Key: HADOOP-10442
> URL: https://issues.apache.org/jira/browse/HADOOP-10442
> Project: Hadoop Common
> Issue Type: Bug
> Affects Versions: 2.3.0, 2.4.0
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Priority: Blocker
> Fix For: 3.0.0, 2.4.0, 2.5.0
>
> Attachments: HADOOP-10442.patch
>
>
> When JniBasedUnixGroupsNetgroupMapping or JniBasedUnixGroupsMapping is used,
> we get segmentation fault very often. The same system ran 2.2 for months
> without any problem, but as soon as upgrading to 2.3, it started crashing.
> This resulted in multiple name node crashes per day.
> The server was running nslcd (nss-pam-ldapd-0.7.5-15.el6_3.2). We did not see
> this problem on the servers running sssd.
> There was one change in the C code and it modified the return code handling
> after getgrouplist() call. If the function returns 0 or a negative value less
> than -1, it will do realloc() instead of returning failure.
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