Crash in sdlwindow_init on FreeBSD

[jbeich]

Locking std::mutex more than once from the same thread (without unlocking first) appears to cause an undefined behavior.
https://en.cppreference.com/w/cpp/thread/mutex/lock

Unlocking std::mutex from a thread that didn't lock it appears to cause an undefined behavior.
https://en.cppreference.com/w/cpp/thread/mutex/unlock

So, adding std::this_thread::sleep_for(3s) between each lock() in order to give time for inputSDLThread to flip g_bSDLInitOK and unlock() doesn't help.

$ sway # parent compositor
$ gamescope vkcube-wayland
00:00:00.000 [backend/headless/backend.c:129] Creating headless backend
00:00:00.047 [render/egl.c:297] Using EGL 1.4
00:00:00.047 [render/egl.c:298] Supported EGL client extensions: EGL_EXT_device_base EGL_EXT_device_enumeration EGL_EXT_device_query EGL_EXT_platform_base EGL_KHR_client_get_all_proc_addresses EGL_EXT_client_extensions EGL_KHR_debug EGL_EXT_platform_device EGL_EXT_platform_wayland EGL_KHR_platform_wayland EGL_EXT_platform_x11 EGL_KHR_platform_x11 EGL_MESA_platform_gbm EGL_KHR_platform_gbm EGL_MESA_platform_surfaceless
00:00:00.047 [render/egl.c:299] Supported EGL display extensions: EGL_ANDROID_blob_cache EGL_ANDROID_native_fence_sync EGL_EXT_create_context_robustness EGL_EXT_image_dma_buf_import EGL_EXT_image_dma_buf_import_modifiers EGL_IMG_context_priority EGL_KHR_config_attribs EGL_KHR_create_context EGL_KHR_create_context_no_error EGL_KHR_fence_sync EGL_KHR_get_all_proc_addresses EGL_KHR_gl_colorspace EGL_KHR_gl_renderbuffer_image EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_3D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_image_base EGL_KHR_no_config_context EGL_KHR_reusable_sync EGL_KHR_surfaceless_context EGL_EXT_pixel_format_float EGL_KHR_wait_sync EGL_MESA_configless_context EGL_MESA_drm_image EGL_MESA_image_dma_buf_export EGL_MESA_query_driver EGL_WL_bind_wayland_display
00:00:00.047 [render/egl.c:300] EGL vendor: Mesa Project
00:00:00.047 [render/egl.c:175] Supported dmabuf buffer formats: AB4H XB4H AR30 XR30 AB30 XB30 AR24 AB24 XR24 XB24 AR15 RG16 R8   R16  GR88 GR32 YUV9 YU11 YU12 YU16 YU24 YVU9 YV11 YV12 YV16 YV24 NV12 P010 P012 P016 NV16 AYUV XYUV YUYV UYVY
00:00:00.049 [render/gles2/renderer.c:693] Using OpenGL ES 3.2 Mesa 20.3.0-devel (git-d1ea49d9244)
00:00:00.049 [render/gles2/renderer.c:694] GL vendor: Intel Open Source Technology Center
00:00:00.049 [render/gles2/renderer.c:695] GL renderer: Mesa DRI Intel(R) HD Graphics 530 (SKL GT2)
00:00:00.049 [render/gles2/renderer.c:696] Supported GLES2 extensions: GL_EXT_blend_minmax GL_EXT_multi_draw_arrays GL_EXT_texture_filter_anisotropic GL_EXT_texture_compression_s3tc GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_rgtc GL_EXT_texture_format_BGRA8888 GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth24 GL_OES_element_index_uint GL_OES_fbo_render_mipmap GL_OES_mapbuffer GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_stencil8 GL_OES_texture_3D GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_half_float GL_EXT_draw_instanced GL_EXT_texture_sRGB_decode GL_OES_EGL_image GL_OES_depth_texture GL_OES_packed_depth_stencil GL_EXT_texture_type_2_10_10_10_REV GL_NV_conditional_render GL_OES_get_program_binary GL_APPLE_texture_max_level GL_EXT_discard_framebuffer GL_EXT_read_format_bgra GL_EXT_frag_depth GL_NV_fbo_color_attachments GL_OES_EGL_image_external GL_OES_EGL_sync GL_OES_vertex_array_object GL_OES_viewport_array GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_EXT_occlusion_query_boolean GL_EXT_robustness GL_EXT_texture_rg GL_EXT_unpack_subimage GL_NV_draw_buffers GL_NV_read_buffer GL_NV_read_depth GL_NV_read_depth_stencil GL_NV_read_stencil GL_EXT_draw_buffers GL_EXT_map_buffer_range GL_KHR_debug GL_KHR_robustness GL_KHR_texture_compression_astc_ldr GL_NV_pixel_buffer_object GL_OES_depth_texture_cube_map GL_OES_required_internalformat GL_OES_surfaceless_context GL_EXT_color_buffer_float GL_EXT_sRGB_write_control GL_EXT_separate_shader_objects GL_EXT_shader_framebuffer_fetch GL_EXT_shader_group_vote GL_EXT_shader_implicit_conversions GL_EXT_shader_integer_mix GL_EXT_tessellation_point_size GL_EXT_tessellation_shader GL_INTEL_conservative_rasterization GL_INTEL_performance_query GL_ANDROID_extension_pack_es31a GL_EXT_base_instance GL_EXT_compressed_ETC1_RGB8_sub_texture GL_EXT_copy_image GL_EXT_draw_buffers_indexed GL_EXT_draw_elements_base_vertex GL_EXT_gpu_shader5 GL_EXT_polygon_offset_clamp GL_EXT_primitive_bounding_box GL_EXT_render_snorm GL_EXT_shader_io_blocks GL_EXT_texture_border_clamp GL_EXT_texture_buffer GL_EXT_texture_cube_map_array GL_EXT_texture_norm16 GL_EXT_texture_view GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent GL_KHR_context_flush_control GL_KHR_robust_buffer_access_behavior GL_NV_image_formats GL_OES_copy_image GL_OES_draw_buffers_indexed GL_OES_draw_elements_base_vertex GL_OES_gpu_shader5 GL_OES_primitive_bounding_box GL_OES_sample_shading GL_OES_sample_variables GL_OES_shader_io_blocks GL_OES_shader_multisample_interpolation GL_OES_tessellation_point_size GL_OES_tessellation_shader GL_OES_texture_border_clamp GL_OES_texture_buffer GL_OES_texture_cube_map_array GL_OES_texture_stencil8 GL_OES_texture_storage_multisample_2d_array GL_OES_texture_view GL_EXT_blend_func_extended GL_EXT_buffer_storage GL_EXT_float_blend GL_EXT_geometry_point_size GL_EXT_geometry_shader GL_EXT_shader_samples_identical GL_KHR_no_error GL_KHR_texture_compression_astc_sliced_3d GL_NV_fragment_shader_interlock GL_OES_EGL_image_external_essl3 GL_OES_geometry_point_size GL_OES_geometry_shader GL_OES_shader_image_atomic GL_EXT_clip_cull_distance GL_EXT_disjoint_timer_query GL_EXT_texture_compression_s3tc_srgb GL_MESA_shader_integer_functions GL_EXT_clip_control GL_EXT_texture_compression_bptc GL_KHR_parallel_shader_compile GL_EXT_EGL_image_storage GL_EXT_shader_framebuffer_fetch_non_coherent GL_EXT_texture_sRGB_R8 GL_EXT_texture_shadow_lod GL_INTEL_blackhole_render GL_MESA_framebuffer_flip_y GL_NV_compute_shader_derivatives GL_EXT_demote_to_helper_invocation GL_EXT_depth_clamp GL_EXT_texture_query_lod
00:00:00.053 [GLES2] FS SIMD8 shader: 5 inst, 0 loops, 30 cycles, 0:0 spills:fills, 1 sends, scheduled with mode top-down, Promoted 0 constants, compacted 80 to 48 bytes.
00:00:00.053 [GLES2] FS SIMD16 shader: 5 inst, 0 loops, 46 cycles, 0:0 spills:fills, 1 sends, scheduled with mode top-down, Promoted 0 constants, compacted 80 to 48 bytes.
00:00:00.053 [GLES2] VS SIMD8 shader: 28 inst, 0 loops, 80 cycles, 0:0 spills:fills, 2 sends, scheduled with mode top-down, Promoted 0 constants, compacted 448 to 336 bytes.
00:00:00.053 [GLES2] FS SIMD16 shader: 2 inst, 0 loops, 12 cycles, 0:0 spills:fills, 1 sends, scheduled with mode (null), Promoted 0 constants, compacted 32 to 32 bytes.
00:00:00.055 [../src/wlserver.cpp:505] Running compositor on wayland display 'gamescope-0'
00:00:00.055 [backend/headless/backend.c:21] Starting headless backend
00:00:00.055 [xwayland/server.c:94] WAYLAND_SOCKET=10 Xwayland :1 -rootless -terminate -listen 8 -listen 9 -wm -1
Process 61071 stopped
* thread #1, name = 'gamescope', stop reason = signal SIGABRT
    frame #0: 0x0000000800ce96ca libc.so.7`__sys_thr_kill at thr_kill.S:4
(lldb) thread backtrace
* thread #1, name = 'gamescope', stop reason = signal SIGABRT
  * frame #0: 0x0000000800ce96ca libc.so.7`__sys_thr_kill at thr_kill.S:4
    frame #1: 0x0000000800c55d14 libc.so.7`__raise(s=6) at raise.c:52:10
    frame #2: 0x0000000800d14fa9 libc.so.7`abort at abort.c:67:8
    frame #3: 0x0000000800b4e939 libcxxrt.so.1`report_failure(err=<unavailable>, thrown_exception=0x00000008048f51c8) at exception.cc:719:5
    frame #4: 0x0000000800b23c8c libc++.so.1`std::__1::__throw_system_error(ev=11, what_arg="mutex lock failed") at system_error.cpp:287:5
    frame #5: 0x0000000800b171cd libc++.so.1`std::__1::mutex::lock(this=<unavailable>) at mutex.cpp:35:9
    frame #6: 0x000000000025da3f gamescope`sdlwindow_init() at sdlwindow.cpp:226:16
    frame #7: 0x0000000000252012 gamescope`initOutput() at main.cpp:208:10
    frame #8: 0x0000000000251fa7 gamescope`main(argc=2, argv=0x00007fffffffe0e8) at main.cpp:182:7
    frame #9: 0x000000000023e80f gamescope`_start(ap=<unavailable>, cleanup=<unavailable>) at crt1_c.c:75:7
(lldb) frame select 6
frame #6: 0x000000000025da3f gamescope`sdlwindow_init() at sdlwindow.cpp:226:16
   223          inputSDLThread.detach();
   224
   225          // When this returns SDL_Init should be over
-> 226          g_SDLInitLock.lock();
   227
   228          return g_bSDLInitOK;
   229  }
(lldb) print g_bSDLInitOK
(bool) $0 = false
(lldb) thread list
Process 61071 stopped
* thread #1: tid = 101977, 0x0000000800ce96ca libc.so.7`__sys_thr_kill at thr_kill.S:4, name = 'gamescope', stop reason = signal SIGABRT
  thread #2: tid = 100617, 0x0000000800b80b8c libthr.so.3`_umtx_op_err at _umtx_op_err.S:40, name = 'gamesco:disk$0'
  thread #3: tid = 100652, 0x0000000800b80b8c libthr.so.3`_umtx_op_err at _umtx_op_err.S:40, name = 'gamesco:disk$1'
  thread #4: tid = 100655, 0x0000000800b80b8c libthr.so.3`_umtx_op_err at _umtx_op_err.S:40, name = 'gamesco:disk$2'
  thread #5: tid = 100660, 0x0000000800b80b8c libthr.so.3`_umtx_op_err at _umtx_op_err.S:40, name = 'gamesco:disk$3'
  thread #6: tid = 100670, 0x0000000800b80b8c libthr.so.3`_umtx_op_err at _umtx_op_err.S:40, name = 'gamescope'
(lldb) thread select 6
(lldb) thread backtrace
* thread #6, name = 'gamescope'
  * frame #0: 0x0000000800b80b8c libthr.so.3`_umtx_op_err at _umtx_op_err.S:40
    frame #1: 0x0000000800b90eb0 libthr.so.3`__thr_rwlock_wrlock(rwlock=<unavailable>, tsp=<unavailable>) at thr_umtx.c:327:10
    frame #2: 0x0000000800b8b301 libthr.so.3`_thr_rtld_wlock_acquire [inlined] _thr_rwlock_wrlock at thr_umtx.h:241:10
    frame #3: 0x0000000800b8b2da libthr.so.3`_thr_rtld_wlock_acquire(lock=0x0000000800b95480) at thr_rtld.c:143
    frame #4: 0x00000008002c933b ld-elf.so.1`wlock_acquire(lock=0x00000008002d72f0, lockstate=0x00007fffdf7f9820) at rtld_lock.c:248:2
    frame #5: 0x00000008002c559c ld-elf.so.1`dlopen_object(name="libXinerama.so.1", fd=-1, refobj=0x00000008002db008, lo_flags=2, mode=2, lockstate=0x00007fffdf7f9820) at rtld.c:3469:2
    frame #6: 0x00000008002c267d ld-elf.so.1`rtld_dlopen(name="libXinerama.so.1", fd=-1, mode=<unavailable>) at rtld.c:3439:13
    frame #7: 0x00000008007a0eda libSDL2-2.0.so.0`SDL_LoadObject_REAL(sofile="libXinerama.so.1") at SDL_sysloadso.c:50:14
    frame #8: 0x00000008007a2bfe libSDL2-2.0.so.0`SDL_X11_LoadSymbols at SDL_x11dyn.c:164:34
    frame #9: 0x00000008007b32e5 libSDL2-2.0.so.0`X11_Available at SDL_x11video.c:99:9
    frame #10: 0x00000008006bfffa libSDL2-2.0.so.0`SDL_VideoInit_REAL(driver_name=0x0000000000000000) at SDL_video.c:504:17
    frame #11: 0x00000008005a7367 libSDL2-2.0.so.0`SDL_InitSubSystem_REAL(flags=16416) at SDL.c:206:17
    frame #12: 0x00000008005a76f3 libSDL2-2.0.so.0`SDL_Init_REAL(flags=16416) at SDL.c:291:12
    frame #13: 0x00000008005cd7ac libSDL2-2.0.so.0`SDL_Init_DEFAULT(a=16416) at SDL_dynapi_procs.h:85:1
    frame #14: 0x00000008005bf877 libSDL2-2.0.so.0`SDL_Init(a=16416) at SDL_dynapi_procs.h:85:1
    frame #15: 0x000000000025d427 gamescope`inputSDLThreadRun() at sdlwindow.cpp:78:7
    frame #16: 0x0000000000251747 gamescope`decltype(__f=0x0000000801a2a948)()>(fp)()) std::__1::__invoke<void (*)()>(void (*&&)()) at type_traits:3899:1
    frame #17: 0x00000000002516b5 gamescope`void std::__1::__thread_execute<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, void (*)()>(__t=0x0000000801a2a940, (null)=__tuple_indices<> @ 0x00007fffdf7f9f68)()>&, std::__1::__tuple_indices<>) at thread:280:5
    frame #18: 0x00000000002510b6 gamescope`void* std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, void (*)()> >(__vp=0x0000000801a2a940) at thread:291:5
    frame #19: 0x0000000800b83999 libthr.so.3`thread_start(curthread=0x0000000804918e00) at thr_create.c:292:16
(lldb) frame select 15
frame #15: 0x000000000025d427 gamescope`inputSDLThreadRun() at sdlwindow.cpp:78:7
   75           SDL_Keymod mod;
   76           uint32_t key;
   77
-> 78           if ( SDL_Init( SDL_INIT_VIDEO | SDL_INIT_EVENTS ) != 0 )
   79           {
   80                   fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
   81                   g_SDLInitLock.unlock();

[emersion]

Right, gamescope has some synchronization issues. Ref #57