[jira] [Commented] (TS-4276) Segmentation fault when hostdb runs out of space

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TS-4276?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15195569#comment-15195569 ] 

ASF GitHub Bot commented on TS-4276:
------------------------------------

GitHub user jacksontj opened a pull request:

    https://github.com/apache/trafficserver/pull/526

    Fix for TS-4276

    In the event that `lookup_done` returns a NULL, we'll reschedule the lookup in the future instead of dumping core.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/jacksontj/trafficserver master

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/trafficserver/pull/526.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #526
    
----
commit 7add326f5020e897bf1ff15b7d9eca14a1adf9dc
Author: Thomas Jackson <ja...@gmail.com>
Date:   2016-03-15T16:15:53Z

    Fix for TS-4276
    
    In the event that `lookup_done` returns a NULL, we'll reschedule the lookup in the future instead of dumping core.

----


> Segmentation fault when hostdb runs out of space
> ------------------------------------------------
>
>                 Key: TS-4276
>                 URL: https://issues.apache.org/jira/browse/TS-4276
>             Project: Traffic Server
>          Issue Type: Bug
>            Reporter: Thomas Jackson
>
> Hostdb assumes that `lookup_done` returns a valid HostDBInfo (as mentioned in comments-- https://github.com/apache/trafficserver/blob/master/iocore/hostdb/HostDB.cc#L1545). In actuality lookup_done can actually return NULL in error conditions-- primarily when it is full (https://github.com/apache/trafficserver/blob/master/iocore/hostdb/HostDB.cc#L1363). Because of this, if a lookup is being done when hostdb is full, r comes back as NULL and we get a segmentation fault that looks like:
> {noformat}
> traffic_server: Segmentation fault (Address not mapped to object [(nil)])
> traffic_server - STACK TRACE: 
> ./bin/traffic_server(_Z19crash_logger_invokeiP9siginfo_tPv+0x8e)[0x4ab81e]
> /lib64/libpthread.so.0(+0x109f0)[0x7f991609a9f0]
> ./bin/traffic_server(_ZN18HostDBContinuation8dnsEventEiP7HostEnt+0xebb)[0x6ad5bb]
> ./bin/traffic_server(_ZN8DNSEntry9postEventEiP5Event+0x45)[0x6c5405]
> ./bin/traffic_server(_ZN7EThread13process_eventEP5Eventi+0x8a)[0x7c2c0a]
> ./bin/traffic_server(_ZN7EThread7executeEv+0x7e8)[0x7c3a38]
> ./bin/traffic_server[0x7c26e5]
> /lib64/libpthread.so.0(+0x760a)[0x7f991609160a]
> /lib64/libc.so.6(clone+0x6d)[0x7f9914fa4a4d]
> Segmentation fault (core dumped)
> {noformat}
> Found while trying to repro TS-4207



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