Segfault with Erlang R21, R22

After upgrading to Erlang R22, my software crashes the Erlang VM with Segmentation fault.

It happens rarely, only after several days of test workload, so I can’t really reproduce.

I made more than 10 core dumps so far, loaded them into gdb, and all of them died at these 2 crash points:

Program terminated with signal 11, Segmentation fault.
#0 process_main (x_reg_array=0x20002, f_reg_array=0x2ade29280590) at x86_64-unknown-linux-gnu/opt/smp/beam_hot.h:4064
4064 if (is_not_tuple(r(0))) {

or

#0 process_main (x_reg_array=0x20002, f_reg_array=0x2) at x86_64-unknown-linux-gnu/opt/smp/beam_hot.h:5252
5252 c_p->seq_trace_lastcnt = unsigned_val(SEQ_TRACE_TOKEN_SERIAL(c_p));

(gdb) print c_p
$1 = <value optimized out>
(gdb) print *c_p
value has been optimized out

The software is not doing any tracing when the crash happens, nor does it have any NIFs.