Debug:

Reading symbols from imaptest...done.
(gdb) run user="puser%d@am.local" users=0-100000 pass=Us123456 host=ha-rr.am.local ssl=any-cert clients=100000 port=993 - secs=300 no_pipelining
Starting program: /usr/bin/imaptest user="puser%d@am.local" users=0-100000 pass=Us123456 host=ha-rr.am.local ssl=any-cert clients=100000 port=993 - secs=300 no_pipelining
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Logi Sele Logo
100% 100% 100%
 179  163  154 551/637 [0%]
 245  247  250 1153/1372 [1%]
 238  240  238 1725/2086 [2%]
 213  215  219 2250/2725 [2%]
 213  209  203 2760/3364 (263 stalled >3s) [3%]
 220  226  228 3308/4024 (854 stalled >3s) [4%]
 247  245  247 3870/4765 (1338 stalled >3s) [4%]
 239  237  239 4414/5482 (1800 stalled >3s) [5%]
 259  257  259 4998/6259 (2299 stalled >3s) [6%]
 270  274  271 5599/7069 (2809 stalled >3s) [7%]
3843   46   26 ms/cmd avg
Logi Sele Logo
100% 100% 100%
 243  242  237 6122/7798 (3369 stalled >3s) [7%]
 242  239  237 6697/8524 (3937 stalled >3s) [8%]
 241  241  248 7251/9247 (4542 stalled >3s) [9%]
 229  231  234 7776/9934 (5143 stalled >3s) [9%]
 230  228  225 8332/10624 (5800 stalled >3s) [10%]

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7f1745f in io_loop_handler_run_internal () from /usr/lib/dovecot/libdovecot.so.0

How can I fix this?