(ITS#8691) slapd crashes during shutdown

[derrick.mckee@gmail.com]

Full_Name: Derrick McKee
Version: OPENLDAP_REL_ENG_2_4_45
OS: Windows
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (2404:f801:8028:1::17f)


Compiling OpenLDAP using clang on Windows with MinGW results in a binary that
crashes during shutdown.  The issue is with mdb_txn_abort in
libraries/liblmdb/mdb.c.  The initial txn does have a non-null child, however,
the address is a garbage address (i.e. containing a mix of 1 and 0 bits set in
the upper 16 bits in a 64-bit pointer).  This seems to indicate that somewhere
the code is expecting a 0 initialized memory area, when it isn't.

How to recreate:

CC=clang CFLAGS="-m64" ./configure --without-threads --without-tls
make depend && make
(using CMD.exe) ./servers/slapd/slapd
<user hits Ctrl-c>