Fix a crash after handling SIGINT and a data race when initializing the Hyprland workspace modules - #3695
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The waybar process does not exit instantaneously.
Signals may be recevied after main has started freeing resources.
When a worker thread is in `fgets` this time window can last forever.
An easy way to duplicate the crash is pressing ^C twice with a Hyprland module.
Thread 1 "waybar" received signal SIGSEGV, Segmentation fault.
spdlog::sinks::sink::should_log (this=0x5f620b542ca5,
msg_level=spdlog::level::info)
at /usr/src/debug/spdlog/spdlog-1.14.1/include/spdlog/sinks/sink-inl.h:13
13 return msg_level >= level_.load(std::memory_order_relaxed);
(gdb) p $_siginfo._sifields._sigfault.si_addr
$1 = (void *) 0x5f620b542cad
`Workspaces::*` and `IPC::startIPC` may both call `getSocketFolder` at the same time.
This randomly causes crashes and/or corruption of the socket path.
Typical crash A:
[2024-10-16 07:42:09.987] [info] Hyprland IPC starting
malloc(): unaligned tcache chunk detected
[2024-10-16 07:42:09.987] [error] Hyprland IPC: Unable to connect?
Thread 1 "waybar" received signal SIGABRT, Aborted.
(gdb) bt
#0 __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
(omitted for brievety)
Alexays#9 0x00007ffff64ae745 in operator new (sz=sz@entry=296) at /usr/src/debug/gcc/gcc/libstdc++-v3/libsupc++/new_op.cc:50
Alexays#10 0x00007ffff65ab1f1 in std::filesystem::__cxx11::path::_List::_Impl::copy (this=0x555555a23350) at /usr/src/debug/gcc/gcc/libstdc++-v3/src/c++17/fs_path.cc:249
Alexays#11 0x00007ffff65ab3bd in std::filesystem::__cxx11::path::_List::_List (this=0x7fffffff9d30, other=<optimized out>) at /usr/src/debug/gcc/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/unique_ptr.h:454
Alexays#12 0x00005555556f4ab1 in waybar::modules::hyprland::IPC::getSocket1Reply(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()
Alexays#13 0x00005555556f5e3d in waybar::modules::hyprland::IPC::getSocket1JsonReply(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()
Alexays#14 0x000055555571289c in waybar::modules::hyprland::Workspaces::setCurrentMonitorId() ()
Typical crash B:
[2024-10-16 10:01:15.859] [info] Hyprland IPC starting
[2024-10-16 10:01:15.859] [info] Loading persistent workspaces from Hyprland workspace rules
Thread 8 "waybar" received signal SIGSEGV, Segmentation fault.
(gdb) bt
#0 std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy
(__d=0x5555558fbca8 "/", __s=0x2973961a26d35726 <error: Cannot access memory at address 0x2973961a26d35726>, __n=1)
at /usr/src/debug/gcc/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.h:433
(omitted for brievety)
Alexays#15 waybar::modules::hyprland::IPC::getSocketFolder[abi:cxx11](char const*)
(instanceSig=0x7fffffffe604 "4520b30d498daca8079365bdb909a8dea38e8d55_1729051218_1982280648") at ../src/modules/hyprland/backend.cpp:41
Alexays#16 0x000055555564230f in waybar::modules::hyprland::IPC::startIPC()::{lambda()Alexays#1}::operator()() const ()
at ../src/modules/hyprland/backend.cpp:70
Alexays#17 0x00007ffff64e1c34 in std::execute_native_thread_routine (__p=0x5555558119c0) at /usr/src/debug/gcc/gcc/libstdc++-v3/src/c++11/thread.cc:104
Alexays#18 0x00007ffff62a339d in start_thread (arg=<optimized out>) at pthread_create.c:447
Contributor
|
On Bug 2: After commenting the lines: if (!socketFolder_.empty()) {
return socketFolder_;
}the problem seems to have dissappeared, but I believe that the mutex is the most adequate solution. Thanks! |
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Bug 1: Crash when receiving signals after
mainreturnsThe waybar process does not exit instantaneously.
Signals may be received after main has started freeing resources.
When a worker thread is in
fgetsthis time window can last forever (until Hyprland writes to the socket).An easy way to duplicate the crash is pressing ^C twice with a Hyprland module waiting on socket2.
Bug 2: Random crashes and/or Hyprland socket connection failure
Workspaces::*andIPC::startIPCmay both callgetSocketFolderat the same time and are racing for the same globalsocketFolder_.This is likely the root cause of #3663.
Typical crash A:
Typical crash B: