mysql_free_result hangs

Once in a while INSERT query hangs for 10+ minutes. Backtrace of the process in hanging state is below. Unfortunately Debian libmariadbclient18 package does not include symbols.

Any ideas what might cause the hang? Is it possible the issue if fixed in newer versions of libmariadbclient?

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Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007fa641ed98a0 in __poll_nocancel () at ../sysdeps/unix/syscall-template.S:84
84 ../sysdeps/unix/syscall-template.S: No such file or directory.
#0 0x00007fa641ed98a0 in __poll_nocancel () at ../sysdeps/unix/syscall-template.S:84
No locals.
#1 0x00007fa63fe5fec1 in ?? () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#2 0x00007fa63fe5ff48 in ?? () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#3 0x00007fa63fe60052 in ?? () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#4 0x00007fa63fe60115 in ?? () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#5 0x00007fa63fe3be51 in ?? () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#6 0x00007fa63fe3ccec in ?? () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#7 0x00007fa63fe2e87f in ?? () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#8 0x00007fa63fe2ffae in mysql_free_result () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#9 0x00007fa63fe31936 in mysql_real_query () from /usr/lib/x86_64-linux-gnu/libmariadbclient.so.18
No symbol table info available.
#10 0x00007fa64040c05c in db_mysql_submit_query (_h=0x7fa641258a90, _s=0x7fa64086b2d0 <sql_str>) at km_dbase.c:112
i = 0
code = 32678
_func_ = "db_mysql_submit_query"
#11 0x00007fa64065ab88 in db_do_submit_query (_h=0x7fa641258a90, _query=0x7fa64086b2d0 <sql_str>, submit_query=0x7fa64040bcf1 <db_mysql_submit_query>) at db_query.c:58
ret = 32678
tvb =

{tv_sec = 94212721508036, tv_usec = 140352034278032}

tve =

{tv_sec = 108261778181, tv_usec = 1382979469336}

tz =

{tz_minuteswest = 24, tz_dsttime = 65147}

tdiff = 908405824
_func_ = "db_do_submit_query"
#12 0x00007fa64065d1ca in db_do_insert_cmd (_h=0x7fa641258a90, _k=0x7fa636252960 <db_keys>, _v=0x7fa636252c40 <db_vals>, _n=24, val2str=0x7fa6404255a6 <db_mysql_val2str>, submit_query=0x7fa64040bcf1 <db_mysql_submit_query>, mode=0) at db_query.c:242
off = 711
ret = 322
...