Package: unixodbc Version: 2.2.14p2-5 Unixodbc is patched to use libltdl
The following stack trace shows a double free coming from lt_dlsetsearchpath() when multithread usage of odbc is being done with FreeSWITCH #0 0x00007f3aed113475 in raise () from /lib/x86_64-linux-gnu/libc.so.6 #1 0x00007f3aed1166f0 in abort () from /lib/x86_64-linux-gnu/libc.so.6 #2 0x00007f3aed14e52b in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #3 0x00007f3aed157d76 in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #4 0x00007f3aed15cb1c in free () from /lib/x86_64-linux-gnu/libc.so.6 #5 0x00007f3aeceddc65 in lt_dlsetsearchpath () from /usr/lib/x86_64-linux-gnu/libltdl.so.7 #6 0x00007f3aeed9c103 in ?? () from /usr/lib/x86_64-linux-gnu/libodbc.so.1 #7 0x00007f3aeed9edfc in SQLConnect () from /usr/lib/x86_64-linux-gnu/libodbc.so.1 According to the documentation at http://www.delorie.com/gnu/docs/libtool/libtool_46.html Note that libltdl is not threadsafe, i.e. a multithreaded application has to use a mutex for libltdl. It was reported that GNU/Linux's glibc 2.0's dlopen with `RTLD_LAZY' (which libltdl uses by default) is not thread-safe, but this problem is supposed to be fixed in glibc 2.1. On the other hand, `RTLD_NOW' was reported to introduce problems in multi-threaded applications on FreeBSD. Working around these problems is left as an exercise for the reader; contributions are certainly welcome. I think the patch needs to be changed to use this lib with a mutex to avoid memory corruption when concurrent calls to opening sql drivers are performed in a multi-threaded app or the use of this libltdl should be discontinued. -- Anthony Minessale II ♬ @anthmfs ♬ @FreeSWITCH ♬ ☞ http://freeswitch.org/ ☞ http://cluecon.com/ ☞ http://twitter.com/FreeSWITCH ☞ irc.freenode.net #freeswitch ☞ *http://freeswitch.org/g+ <http://freeswitch.org/g+>* ClueCon Weekly Development Call ☎ sip:[email protected] ☎ +19193869900
