multipassd SEGV on removing / launching instances

[Saviq]

Hoping this gives enough data to dig - going through a dance of:

$ multipass launch http://cdimage.ubuntu.com/ubuntu-core/18/stable/current/ubuntu-core-18-amd64.img.xz
Ctrl^C
$ multipass delete -p
# rinse and repeat

I saw multipassd crashing a couple times, and I managed to get a traceback from one of those, here's a snippet:

#0  0x00007f2d04000ae8 in ?? ()                                                                                                                                                                                                               
No symbol table info available.                                                                                                                                                                                                               
#1  0x0000000000591cac in grpc::internal::WriterInterface<multipass::LaunchReply>::Write (msg=..., this=<optimized out>) at /build/multipass/parts/multipass/src/3rd-party/grpc/include/grpcpp/impl/codegen/sync_stream.h:124                 
No locals.                                                                                                                                                                                                                                    
#2  multipass::Daemon::<lambda(const multipass::VirtualMachineDescription&)>::operator()(const multipass::VirtualMachineDescription &) const (__closure=0x1e779a0, vm_desc=...)                                                               
    at /build/multipass/parts/multipass/src/src/daemon/daemon.cpp:1870                                                                                                                                                                        
        reply = {<google::protobuf::Message> = {<google::protobuf::MessageLite> = {_vptr.MessageLite = 0xcb2d58 <vtable for multipass::LaunchReply+16>}, <No data fields>}, static kIndexInFileMessages = 8, static kLogLineFieldNumber = 6,  
          static kReplyMessageFieldNumber = 8, static kMetricsShowInfoFieldNumber = 5, static kUpdateInfoFieldNumber = 7, static kMetricsPendingFieldNumber = 4, static kVmInstanceNameFieldNumber = 1,                                       
          static kLaunchProgressFieldNumber = 2, static kCreateMessageFieldNumber = 3,                                                                                                                                                        
          _internal_metadata_ = {<google::protobuf::internal::InternalMetadataWithArenaBase<google::protobuf::UnknownFieldSet, google::protobuf::internal::InternalMetadataWithArena>> = {ptr_ = 0x0, static kPtrTagMask = <optimized out>,   
              static kPtrValueMask = <optimized out>}, <No data fields>}, log_line_ = {ptr_ = 0xcd4d40 <google::protobuf::internal::fixed_address_empty_string[abi:cxx11]>}, reply_message_ = {                                               
            ptr_ = 0xcd4d40 <google::protobuf::internal::fixed_address_empty_string[abi:cxx11]>}, metrics_show_info_ = 0x0, update_info_ = 0x0, metrics_pending_ = false, create_oneof_ = {vm_instance_name_ = {ptr_ = 0x1e747c0},            
            launch_progress_ = 0x1e747c0, create_message_ = {ptr_ = 0x1e747c0}}, _cached_size_ = {size_ = {<std::__atomic_base<int>> = {static _S_alignment = 4, _M_i = 0}, <No data fields>}}, _oneof_case_ = {3}}                           
        vm = <optimized out>                                                                                                                                                                                                                  
        future_watcher = <optimized out>                                                                                                                                                                                                      
        start = true                                                                                                                                                                                                                          
        name = {static npos = 18446744073709551615, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x1e779c8 "fearless-kakapo"}, _M_string_length = 15, {          
            _M_local_buf = "fearless-kakapo", _M_allocated_capacity = 8319104453133296998}}                                                                                                                                                   
        status_promise = 0x7f2d2742c660                                                                                                                                                                                                       
        server = 0x7f2d2742c770                                                                                                                                                                                                               
        this = 0x7ffce35d0780                                                                                                                                                                                                                 
#3  0x00007f2d35a86122 in QObject::event(QEvent*) () from /snap/multipass/758/bin/../usr/lib/x86_64-linux-gnu/libQt5Core.so.5                                                                                                                 
No symbol table info available.
#4  0x00007f2d35a56991 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /snap/multipass/758/bin/../usr/lib/x86_64-linux-gnu/libQt5Core.so.5                                                                                    
No symbol table info available.                                                                                                                                                                                                               
#5  0x00007f2d35a5911d in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /snap/multipass/758/bin/../usr/lib/x86_64-linux-gnu/libQt5Core.so.5                                                                  
No symbol table info available.                                                                                                                                                                                                               
#6  0x00007f2d35ab02c3 in ?? () from /snap/multipass/758/bin/../usr/lib/x86_64-linux-gnu/libQt5Core.so.5                                                                                                                                      
No symbol table info available.                                                                                                                                                                                                               
#7  0x00007f2d31c39197 in g_main_context_dispatch () from /snap/core/current/lib/x86_64-linux-gnu/libglib-2.0.so.0                                                                                                                            
No symbol table info available.                                                                                                                                                                                                               
#8  0x00007f2d31c393f0 in ?? () from /snap/core/current/lib/x86_64-linux-gnu/libglib-2.0.so.0                                                                                                                                                 
No symbol table info available.                                                                                                                                                                                                               
#9  0x00007f2d31c3949c in g_main_context_iteration () from /snap/core/current/lib/x86_64-linux-gnu/libglib-2.0.so.0                                                                                                                           
No symbol table info available.                                                                                                                                                                                                               
#10 0x00007f2d35aaf8ef in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /snap/multipass/758/bin/../usr/lib/x86_64-linux-gnu/libQt5Core.so.5                                                              
No symbol table info available.                                                                                                                                                                                                               
#11 0x00007f2d35a549ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /snap/multipass/758/bin/../usr/lib/x86_64-linux-gnu/libQt5Core.so.5                                                                                 
No symbol table info available.                                                                                                                                                                                                               
#12 0x00007f2d35a5da84 in QCoreApplication::exec() () from /snap/multipass/758/bin/../usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.
#13 0x0000000000571e47 in main (argc=5, argv=<optimized out>) at /build/multipass/parts/multipass/src/src/daemon/daemon_main.cpp:123
…

[gerboland]

I also can get a different stacktrace:

#0  QProcess::state (this=0x0) at io/qprocess.cpp:1756
#1  0x0000555555c3cddd in multipass::QemuVirtualMachine::ensure_vm_is_running() ()
#2  0x0000555555c41d25 in void std::__invoke_impl<void, void (multipass::QemuVirtualMachine::*&)(), multipass::QemuVirtualMachine*&>(std::__invoke_memfun_deref, void (multipass::QemuVirtualMachine::*&)(), multipass::QemuVirtualMachine*&) ()
#3  0x0000555555c41972 in std::__invoke_result<void (multipass::QemuVirtualMachine::*&)(), multipass::QemuVirtualMachine*&>::type std::__invoke<void (multipass::QemuVirtualMachine::*&)(), multipass::QemuVirtualMachine*&>(void (multipass::QemuVirtualMachine::*&)(), multi
pass::QemuVirtualMachine*&) ()
#4  0x0000555555c4140f in void std::_Bind<void (multipass::QemuVirtualMachine::*(multipass::QemuVirtualMachine*))()>::__call<void, , 0ul>(std::tuple<>&&, std::_Index_tuple<0ul>) ()
#5  0x0000555555c40e09 in void std::_Bind<void (multipass::QemuVirtualMachine::*(multipass::QemuVirtualMachine*))()>::operator()<, void>() ()
#6  0x0000555555c40777 in std::_Function_handler<void (), std::_Bind<void (multipass::QemuVirtualMachine::*(multipass::QemuVirtualMachine*))()> >::_M_invoke(std::_Any_data const&) ()
#7  0x0000555555c5fa44 in std::function<void ()>::operator()() const ()
#8  0x0000555555c5cf12 in multipass::utils::wait_until_ssh_up(multipass::VirtualMachine*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::function<void ()> const&)::{lambda()#1}::operator()() const ()
#9  0x0000555555c5de57 in void multipass::utils::try_action_for<multipass::utils::wait_until_ssh_up(multipass::VirtualMachine*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::function<void ()> const&)::{lambda()#2}&, multipass::utils::wait_until_ssh_up(multip
ass::VirtualMachine*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::function<void ()> const&)::{lambda()#1}&>(multipass::utils::wait_until_ssh_up(multipass::VirtualMachine*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::function<void ()> const&):
:{lambda()#2}&, std::chrono::duration<long, std::ratio<1l, 1000l> >, multipass::utils::wait_until_ssh_up(multipass::VirtualMachine*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::function<void ()> const&)::{lambda()#1}&) ()
#10 0x0000555555c5d200 in multipass::utils::wait_until_ssh_up(multipass::VirtualMachine*, std::chrono::duration<long, std::ratio<1l, 1000l> >, std::function<void ()> const&) ()
#11 0x0000555555c3d24c in multipass::QemuVirtualMachine::wait_until_ssh_up(std::chrono::duration<long, std::ratio<1l, 1000l> >) ()
#12 0x0000555555bad000 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > multipass::Daemon::async_wait_for_ssh_and_start_mounts_for<multipass::LaunchReply>(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > c
onst&, grpc::ServerWriter<multipass::LaunchReply>*) ()
#13 0x0000555555bd3797 in QtConcurrent::StoredMemberFunctionPointerCall2<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, multipass::Daemon, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cx
x11::basic_string<char, std::char_traits<char>, std::allocator<char> >, grpc::ServerWriter<multipass::LaunchReply>*, grpc::ServerWriter<multipass::LaunchReply>*>::runFunctor() ()
#14 0x0000555555bd3611 in QtConcurrent::RunFunctionTask<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::run() ()
#15 0x00007ffff63332b2 in QThreadPoolThread::run (this=0x7fffb80155b0) at thread/qthreadpool.cpp:99
#16 0x00007ffff633617d in QThreadPrivate::start (arg=0x7fffb80155b0) at thread/qthread_unix.cpp:368
#17 0x00007ffff69dc6db in start_thread (arg=0x7fffc9ffb700) at pthread_create.c:463
#18 0x00007ffff567b88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

[townsend2010]

Having looked at the two traces in here, I think @Saviq's and @gerboland's issues are different. I'm pretty sure @Saviq's issue is fixed by #741 because I saw a similar traceback when working on that fix.

Also I have found the root cause of @gerboland's traceback and it's a separate issue. I'm just going to open a new bug for @gerboland's issue and I'm going to close this one since I'm pretty sure it's fixed.