+++ This bug was initially created as a clone of Bug #1505325 +++

+++ This bug was initially created as a clone of Bug #1503405 +++

Description of problem:

Our code scanner has reported a potential null pointer dereference at xlators/features/changelog/lib/src/gf-history-changelog.c

        xlator_t                       *this                    = NULL;
    ........

        pthread_attr_t attr;

        ret = pthread_attr_init (&attr);
        if (ret != 0) {
                gf_msg (this->name, GF_LOG_ERROR, errno,    // <== `this` variable is still NULL at this time. 
                        CHANGELOG_LIB_MSG_PTHREAD_ERROR,
                        "Pthread init failed");
                return -1;
        }

        this = THIS;  // `this` variable gets assignment here, it was NULL before that
        if (!this) {
                ret = -1;
                goto out;
        }

according to the documentation of pthread_attr_init, the chance of its invocation failure is low, but once happened, the process will crash (the GEO replication syncdaemon seems using this function).

Regards,
Alex, SourceBrella Inc.

--- Additional comment from Worker Ant on 2017-10-23 06:52:33 EDT ---

REVIEW: https://review.gluster.org/18553 (libgfchangelog: Fix possible null pointer dereference) posted (#1) for review on master by Kotresh HR (khiremat)

--- Additional comment from Worker Ant on 2017-10-24 01:25:01 EDT ---

COMMIT: https://review.gluster.org/18553 committed in master by Aravinda VK (avishwan) 
------
commit 738c38f0efa7b4d4dab0cf23d00589d68e4eb88d
Author: Kotresh HR <khiremat>
Date:   Mon Oct 23 06:46:49 2017 -0400

    libgfchangelog: Fix possible null pointer dereference
    
    If pthread_attr_init fails, gf_msg uses this->name
    where 'this' is not initialized yet. This patch fixes
    the same.
    
    Change-Id: Ie004cbe1015a0d62fc3b5512e8954c5606eeeb5f
    Signed-off-by: Kotresh HR <khiremat>
    BUG: 1505325