Segmentation fault found when using gdb debug

[FanWan]

Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fffdadb1700 (LWP 14062)] 0x0000000000834cc4 in aho_corasick::state::next_state(char, bool) const () at /home/opt/compiler/gcc-8.2/gcc-8.2/include/c++/8.2.0/bits/stl_tree.h:2549 2549 _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::

#0 0x0000000000834cc4 in aho_corasick::state::next_state(char, bool) const () at /home/opt/compiler/gcc-8.2/gcc-8.2/include/c++/8.2.0/bits/stl_tree.h:2549

[FanWan]

crash occured in concurrent context, such as such as 100qps of reading threads and a crontab writing thread.

Shared read lock is used when searching while exclusive write lock is used when updating