SIGSEGV on running text/expirations.test.py (fiber 1 is switched while running GC finalizer (i.e. __gc metamethod))

[ligurio]

[005] binary/binary-expire.test.py                                    [ pass ]
[005]
[005]
[005] [Instance "binary" returns with non-zero exit code: 1]
[005]
[005] [test-run server "binary"] Last 15 lines of the log file /tmp/t/005_binary/binary.log:
[005] #8  0x5616a2778c42 in lj_ccall_func+898
[005] #9  0x5616a2749580 in lj_cf_ffi_meta___call+176
[005] #10 0x5616a272abb3 in lj_BC_FUNCC+70
[005] #11 0x5616a27342f5 in gc_call_finalizer.isra.0+133
[005] #12 0x5616a273545c in lj_gc_finalize_cdata+140
[005] #13 0x5616a2737bcd in cpfinalize+13
[005] #14 0x5616a272afa4 in lj_vm_cpcall+86
[005] #15 0x5616a2737f91 in lua_close+177
[005] #16 0x5616a26ba254 in tarantool_lua_free+260
[005] #17 0x5616a24ce690 in main+2480
[005] #18 0x7f84e6011083 in __libc_start_main+243
[005] #19 0x5616a24cf11e in _start+46
[005] 2024-10-11 14:05:40.750 [3951] main C> fiber 1 is switched while running GC finalizer (i.e. __gc metamethod)
[005] 2024-10-11 14:05:40.750 [3951] main I> destroying slab cache
[005] 2024-10-11 14:05:40.750 [3951] main I> destroying arena...

main C> fiber 1 is switched while running GC finalizer (i.e. __gc metamethod)

Source: https://github.com/tarantool/tarantool/blob/a4b4158f2196442308aba7df8f8e21b98b5319fc/src/lua/utils.c#L1155
CI: https://github.com/tarantool/tarantool/actions/runs/11293697488/job/31413793885?pr=10632#step:9:115

Tarantool version: master, 47295fdebc1910b990c391c26fe92918a9c0c001
memcached version: c5fd957

Full log: job-logs.txt

[Totktonada]

This GC hook:

memcached/memcached/init.lua

Line 397 in c5fd957

instance.service = ffi.gc(service, memcached_internal.memcached_free)

Yields:

memcached/memcached/internal/memcached.c

Lines 305 to 311 in c5fd957

	void
	memcached_free(struct memcached_service *srv)
	{
	memcached_stop(srv);
	if (srv) free((void *)srv->name);
	free(srv);
	}

memcached/memcached/internal/memcached.c

Lines 322 to 328 in c5fd957

	void
	memcached_stop (struct memcached_service *srv)
	{
	memcached_expire_stop(srv);
	while (srv->stat.curr_conns != 0)
	fiber_sleep(0.001);
	}

Igor doesn't like such hooks.