ATS crashes when reloading parent.config

[kanseiishikawa]

Happened

A crash occurred while using ATS9.2.11

Thread 1562, [ET_NET 57]:
0    0x0000557bbf45a498 crash_logger_invoke(int, siginfo_t*, void*) + 0x88
1    0x00007fb9728d1520 __sigaction + 0x50
2    0x0000557bbf53abd2 HttpTransact::handle_request_keep_alive_headers(HttpTransact::State*, HTTPVersion, HTTPHdr*) + 0x32
3    0x0000557bbf53f039 HttpTransact::build_request(HttpTransact::State*, HTTPHdr*, HTTPHdr*, HTTPVersion) + 0xb9
4    0x0000557bbf51e584 HttpTransact::HandleCacheOpenReadHit(HttpTransact::State*) + 0x834
5    0x0000557bbf4f9941 HttpSM::call_transact_and_set_next_state(void (*)(HttpTransact::State*)) + 0x201
6    0x0000557bbf4d7cf2 HttpSM::state_api_callout(int, void*) + 0x592
7    0x0000557bbf4d3eec HttpSM::state_api_callback(int, void*) + 0xec
8    0x0000557bbf47a2fb TSHttpTxnReenable + 0x18b
9    0x00007fb96f625226 0x0 + 0x18b

It occurred at the moment parent.config was reloaded.

My investigation

Based on the code and this stack trace, I suspect the issue is occurring at position HttpTransact.cc#L6889.
build_request is called after the null check for HttpTransact.cc#L2931, but it appears there is no subsequent null check.

I would like to know the following

• Is it possible for execution to reach point HttpTransact.cc#L6889 with s->current.server being null?
• Are there any other possible causes?

Any help would be appreciated