Submitted by: @AlexPeshkoff

First look at a problem I failed to solve it. Here is backtrace:
#⁠0 0x00002aaaab6c77f9 in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#⁠1 0x00002aaaab6c8f2c in *__GI_abort () at ../sysdeps/generic/abort.c:88
#⁠2 0x00000000006753da in Firebird::Vector<Firebird::BlockInfo, 25ul>::join (this=0x2aaaaccffe70, L=@0x2aaaaab23e50)
at vector.h:81
#⁠3 0x00000000006752d2 in Firebird::BePlusTree<Firebird::BlockInfo, unsigned long, Firebird::MemoryPool::InternalAllocator, Firebird::BlockInfo, Firebird::DefaultComparator<unsigned long>, 25, 375>::Accessor::fastRemove (this=0x2aaaaab14050)
at tree.h:395
#⁠4 0x0000000000673fb9 in Firebird::BePlusTree<Firebird::BlockInfo, unsigned long, Firebird::MemoryPool::InternalAllocator, Firebird::BlockInfo, Firebird::DefaultComparator<unsigned long>, 25, 375>::fastRemove (this=0x2aaaaab14038) at tree.h:180
#⁠5 0x0000000000671e50 in Firebird::MemoryPool::internal_alloc (this=0x2aaaaab14030, size=3040, type=-4, file=0x0, line=0)
at ../src/common/classes/alloc.cpp:1314
#⁠6 0x000000000066fcfc in Firebird::MemoryPool::updateSpare (this=0x2aaaaab14030) at ../src/common/classes/alloc.cpp:303
#⁠7 0x0000000000671ac6 in Firebird::MemoryPool::deletePool (pool=0x2aaaacd87d08) at ../src/common/classes/alloc.cpp:1227
#⁠8 0x00000000004b5589 in JrdMemoryPool::deletePool (pool=0x2aaaacd87d08) at ../src/jrd/all.cpp:113
#⁠9 0x00000000004e29a2 in CMP_release (tdbb=0x43004b60, request=0x2aaaacd88248) at ../src/jrd/cmp.cpp:2364
#⁠10 0x0000000000542415 in purge_attachment (tdbb=0x43004b60, user_status=0x43004e60, attachment=0x2aaaacd03d90,
force_flag=false) at ../src/jrd/jrd.cpp:7040
#⁠11 0x0000000000539a90 in jrd8_detach_database (user_status=0x43004e60, handle=0x2aaaaaade150) at ../src/jrd/jrd.cpp:2354
#⁠12 0x0000000000439ad6 in isc_detach_database (user_status=0x43004e60, handle=0x2aaaaab01ef4) at ../src/jrd/why.cpp:1928
#⁠13 0x0000000000411e49 in rem_port::end_database (this=0x2aaaacd3c020, release=0x2aaaaaafeaa8, sendL=0x2aaaaaafe4c0)
at ../src/remote/server.cpp:1775
#⁠14 0x0000000000415eb6 in process_packet (port=0x2aaaacd3c020, sendL=0x2aaaaaafe4c0, receive=0x2aaaaaafe918,
result=0x43005108) at ../src/remote/server.cpp:3493
(More stack frames follow...)
(gdb) bt 17
#⁠0 0x00002aaaab6c77f9 in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#⁠1 0x00002aaaab6c8f2c in *__GI_abort () at ../sysdeps/generic/abort.c:88
#⁠2 0x00000000006753da in Firebird::Vector<Firebird::BlockInfo, 25ul>::join (this=0x2aaaaccffe70, L=@0x2aaaaab23e50)
at vector.h:81
#⁠3 0x00000000006752d2 in Firebird::BePlusTree<Firebird::BlockInfo, unsigned long, Firebird::MemoryPool::InternalAllocator, Firebird::BlockInfo, Firebird::DefaultComparator<unsigned long>, 25, 375>::Accessor::fastRemove (this=0x2aaaaab14050)
at tree.h:395
#⁠4 0x0000000000673fb9 in Firebird::BePlusTree<Firebird::BlockInfo, unsigned long, Firebird::MemoryPool::InternalAllocator, Firebird::BlockInfo, Firebird::DefaultComparator<unsigned long>, 25, 375>::fastRemove (this=0x2aaaaab14038) at tree.h:180
#⁠5 0x0000000000671e50 in Firebird::MemoryPool::internal_alloc (this=0x2aaaaab14030, size=3040, type=-4, file=0x0, line=0)
at ../src/common/classes/alloc.cpp:1314
#⁠6 0x000000000066fcfc in Firebird::MemoryPool::updateSpare (this=0x2aaaaab14030) at ../src/common/classes/alloc.cpp:303
#⁠7 0x0000000000671ac6 in Firebird::MemoryPool::deletePool (pool=0x2aaaacd87d08) at ../src/common/classes/alloc.cpp:1227
#⁠8 0x00000000004b5589 in JrdMemoryPool::deletePool (pool=0x2aaaacd87d08) at ../src/jrd/all.cpp:113
#⁠9 0x00000000004e29a2 in CMP_release (tdbb=0x43004b60, request=0x2aaaacd88248) at ../src/jrd/cmp.cpp:2364
#⁠10 0x0000000000542415 in purge_attachment (tdbb=0x43004b60, user_status=0x43004e60, attachment=0x2aaaacd03d90,
force_flag=false) at ../src/jrd/jrd.cpp:7040
#⁠11 0x0000000000539a90 in jrd8_detach_database (user_status=0x43004e60, handle=0x2aaaaaade150) at ../src/jrd/jrd.cpp:2354
#⁠12 0x0000000000439ad6 in isc_detach_database (user_status=0x43004e60, handle=0x2aaaaab01ef4) at ../src/jrd/why.cpp:1928
#⁠13 0x0000000000411e49 in rem_port::end_database (this=0x2aaaacd3c020, release=0x2aaaaaafeaa8, sendL=0x2aaaaaafe4c0)
at ../src/remote/server.cpp:1775
#⁠14 0x0000000000415eb6 in process_packet (port=0x2aaaacd3c020, sendL=0x2aaaaaafe4c0, receive=0x2aaaaaafe918,
result=0x43005108) at ../src/remote/server.cpp:3493
#⁠15 0x00000000004191f2 in loopThread (flags=0x2) at ../src/remote/server.cpp:5349

Should notice, that at frame 2 we try to join vector, containing not initialized data (feedabed).