# gdb --batch /opt/couchbase/bin/memcached -p 104685 -ex "bt full" -ex quit
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[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00007f48b299b483 in epoll_wait () at ../sysdeps/unix/syscall-template.S:81
81	T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
warning: File "/opt/couchbase/lib/libstdc++.so.6.0.28-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load:/usr/bin/mono-gdb.py".
To enable execution of this file add
	add-auto-load-safe-path /opt/couchbase/lib/libstdc++.so.6.0.28-gdb.py
line to your configuration file "/root/.gdbinit".
To completely disable this security protection add
	set auto-load safe-path /
line to your configuration file "/root/.gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
	info "(gdb)Auto-loading safe path"
#0  0x00007f48b299b483 in epoll_wait () at ../sysdeps/unix/syscall-template.S:81
No locals.
#1  0x00007f48b432e3c5 in epoll_dispatch (base=0x7f48b1666300, tv=<optimized out>) at /home/couchbase/jenkins/workspace/cbdeps-platform-build-old/deps/packages/build/libevent/libevent-prefix/src/libevent/epoll.c:465
        epollop = 0x7f48b16c1940
        events = 0x7f48b16a4380
        i = <optimized out>
        res = <optimized out>
        timeout = <optimized out>
        __func__ = "epoll_dispatch"
#2  0x00007f48b4325376 in event_base_loop (base=0x7f48b1666300, flags=1) at /home/couchbase/jenkins/workspace/cbdeps-platform-build-old/deps/packages/build/libevent/libevent-prefix/src/libevent/event.c:1998
        evsel = 0x7f48b4538c20 <epollops>
        tv = {
          tv_sec = 0,
          tv_usec = 999000
        }
        tv_p = <optimized out>
        res = <optimized out>
        done = 0
        retval = 0
        __func__ = "event_base_loop"
#3  0x0000000000c11297 in folly::EventBase::loopBody (this=this@entry=0x7f48b164b500, flags=flags@entry=0, ignoreKeepAlive=ignoreKeepAlive@entry=false) at /home/couchbase/jenkins/workspace/cbdeps-platform-build-old/deps/packages/build/folly/folly-prefix/src/folly/folly/io/async/EventBase.cpp:397
        callbacks = {
          <boost::intrusive::list_impl<boost::intrusive::bhtraits<folly::EventBase::LoopCallback, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)2, boost::intrusive::dft_tag, 1>, unsigned long, false, void>> = {
            static constant_time_size = false,
            static stateful_value_traits = <optimized out>,
            static has_container_from_iterator = <optimized out>,
            static safemode_or_autounlink = true,
            data_ = {
              <boost::intrusive::bhtraits<folly::EventBase::LoopCallback, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)2, boost::intrusive::dft_tag, 1>> = {
                <boost::intrusive::bhtraits_base<folly::EventBase::LoopCallback, boost::intrusive::list_node<void*>*, boost::intrusive::dft_tag, 1>> = {<No data fields>},
                members of boost::intrusive::bhtraits<folly::EventBase::LoopCallback, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)2, boost::intrusive::dft_tag, 1>:
                static link_mode = boost::intrusive::auto_unlink
              },
              members of boost::intrusive::list_impl<boost::intrusive::bhtraits<folly::EventBase::LoopCallback, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)2, boost::intrusive::dft_tag, 1>, unsigned long, false, void>::data_t:
              root_plus_size_ = {
                <boost::intrusive::detail::size_holder<false, unsigned long, void>> = {
                  static constant_time_size = <optimized out>
                },
                members of boost::intrusive::list_impl<boost::intrusive::bhtraits<folly::EventBase::LoopCallback, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)2, boost::intrusive::dft_tag, 1>, unsigned long, false, void>::root_plus_size:
                m_header = {
                  <boost::intrusive::list_node<void*>> = {
                    next_ = 0x7fff16f165b0,
                    prev_ = 0x7fff16f165b0
                  }, <No data fields>}
              }
            }
          }, <No data fields>}
        message = 0xcdb968 "Your code just tried to loop over an event base from inside another event base loop. Since libevent is not reentrant, this leads to undefined behavior in opt builds. Please fix immediately. For the co"...
        SCOPE_EXIT_STATE13 = {
          <folly::detail::ScopeGuardImplBase> = {
            dismissed_ = false
          },
          members of folly::detail::ScopeGuardImpl<folly::EventBase::loopBody(int, bool)::<lambda()>, true>:
          function_ = {
            __this = 0x7f48b164b500
          }
        }
        res = 0
        ranLoopCallbacks = <optimized out>
        blocking = true
        once = false
        prev = {
          __d = {
            __r = 36388589609099934
          }
        }
        idleStart = {
          __d = {
            __r = 36390865006155969
          }
        }
        busy = <optimized out>
        idle = <optimized out>
        prevLoopThread = {
          _M_thread = 0
        }
#4  0x0000000000c11766 in folly::EventBase::loop (this=this@entry=0x7f48b164b500) at /home/couchbase/jenkins/workspace/cbdeps-platform-build-old/deps/packages/build/folly/folly-prefix/src/folly/folly/io/async/EventBase.cpp:315
        guard = {
          list_ = {
            forbid = true,
            prev = 0x0,
            curr = {
              name = {
                static npos = <optimized out>,
                b_ = 0xcdb5db "EventBase",
                e_ = 0xcdb5e4 ""
              }
            }
          }
        }
#5  0x0000000000c13126 in folly::EventBase::loopForever (this=0x7f48b164b500) at /home/couchbase/jenkins/workspace/cbdeps-platform-build-old/deps/packages/build/folly/folly-prefix/src/folly/folly/io/async/EventBase.cpp:538
        ret = <optimized out>
#6  0x000000000056a78b in memcached_main(int, char**) () at /home/couchbase/jenkins/workspace/couchbase-server-unix/kv_engine/daemon/memcached.cc:1033
        numa_status = {
          static npos = 18446744073709551615,
          _M_dataplus = {
            <std::allocator<char>> = {
              <__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>},
            members of std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider:
            _M_p = 0x7f48b1621680 "Set memory allocation policy to 'interleave'"
          },
          _M_string_length = 44,
          {
            _M_local_buf = ",", '\000' <repeats 14 times>,
            _M_allocated_capacity = 44
          }
        }
        parent_monitor = {
          _M_t = {
            <std::__uniq_ptr_impl<ProcessMonitor, std::default_delete<ProcessMonitor> >> = {
              _M_t = {
                <std::_Tuple_impl<0, ProcessMonitor*, std::default_delete<ProcessMonitor> >> = {
                  <std::_Tuple_impl<1, std::default_delete<ProcessMonitor> >> = {
                    <std::_Head_base<1, std::default_delete<ProcessMonitor>, true>> = {
                      <std::default_delete<ProcessMonitor>> = {<No data fields>}, <No data fields>}, <No data fields>},
                  <std::_Head_base<0, ProcessMonitor*, false>> = {
                    _M_head_impl = 0x0
                  }, <No data fields>}, <No data fields>}
            }, <No data fields>}
        }
        fineClock = {
          overhead = {
            __r = 774
          },
          measurementPeriod = {
            __r = 1
          }
        }
        coarseClock = {
          overhead = {
            __r = 10
          },
          measurementPeriod = {
            __r = 1
          }
        }
        phosphor_internal_category_enabled_999 = {
          _M_b = {
            _M_p = 0x7f48b569669b <phosphor::TraceLog::getInstance()::log_instance+8283>
          },
          static is_always_lock_free = <optimized out>
        }
        phosphor_internal_category_enabled_temp_999 = <optimized out>
        phosphor_internal_tpi_999 = {
          category = 0xc567df "memcached",
          name = 0xcbd54c "Started",
          type = phosphor::GlobalInstant,
          argument_names = {
            _M_elems = {0xcc1882 "", 0xcc1882 ""}
          },
          argument_types = {
            _M_elems = {phosphor::is_none, phosphor::is_none}
          }
        }
#7  0x00007f48b28bf3d5 in __libc_start_main (main=0x53ff60 <main(int, char**)>, argc=3, argv=0x7fff16f16f98, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff16f16f88) at ../csu/libc-start.c:266
        result = <optimized out>
        unwind_buf = {
          cancel_jmp_buf = {{
              jmp_buf = {0, -7666890964112495659, 5646846, 140733578309520, 0, 0, 7667262542643473365, 7712658856768580565},
              mask_was_saved = 0
            }},
          priv = {
            pad = {0x0, 0x0, 0x7f48b5f948f3 <_dl_init+275>, 0x7f48b61a8150},
            data = {
              prev = 0x0,
              cleanup = 0x0,
              canceltype = -1241954061
            }
          }
        }
        not_first_call = <optimized out>
#8  0x0000000000562a27 in _start () at /opt/gcc-10.2.0/include/c++/10.2.0/bits/char_traits.h:322
No symbol table info available.
A debugging session is active.