Multiple data races in CJobPool

[ceeac]

Steps to reproduce:

• Compile and link with GCC/Clang with -fsanitize=thread
• Run the server

Result:

==================
WARNING: ThreadSanitizer: data race (pid=87358)
  Read of size 4 at 0x7b68000006c0 by main thread:
    #0 CJob::Status() const teeworlds/src/engine/shared/jobs.h:35:30 (teeworlds_srv+0x548911)
    #1 CMasterServer::Update() teeworlds/src/engine/shared/masterserver.cpp:75:42 (teeworlds_srv+0x54837b)
    #2 CRegister::RegisterUpdate(int) teeworlds/src/engine/server/register.cpp:110:19 (teeworlds_srv+0x4c401b)
    #3 CServer::Run() teeworlds/src/engine/server/server.cpp:1442:15 (teeworlds_srv+0x4cf60c)
    #4 main teeworlds/src/engine/server/server.cpp:1942:21 (teeworlds_srv+0x4d3192)

  Previous write of size 4 at 0x7b68000006c0 by thread T1:
    #0 CJobPool::WorkerThread(void*) teeworlds/src/engine/shared/jobs.cpp:59:19 (teeworlds_srv+0x542e41)
    #1 thread_run teeworlds/src/base/system.c:516:2 (teeworlds_srv+0x570b41)

  Location is heap block of size 1480 at 0x7b6800000600 allocated by main thread:
    #0 operator new(unsigned long) <null> (teeworlds_srv+0x4c2796)
    #1 CreateEngineMasterServer() teeworlds/src/engine/shared/masterserver.cpp:211:58 (teeworlds_srv+0x54755e)
    #2 main teeworlds/src/engine/server/server.cpp:1888:45 (teeworlds_srv+0x4d2a07)

  Thread T1 (tid=87361, running) created by main thread at:
    #0 pthread_create <null> (teeworlds_srv+0x45138b)
    #1 thread_init teeworlds/src/base/system.c:533:6 (teeworlds_srv+0x570aa9)
    #2 CEngine::CEngine(char const*) teeworlds/src/engine/shared/engine.cpp:67:13 (teeworlds_srv+0x53e74b)
    #3 CreateEngine(char const*) teeworlds/src/engine/shared/engine.cpp:176:58 (teeworlds_srv+0x53e54a)
    #4 main teeworlds/src/engine/server/server.cpp:1883:21 (teeworlds_srv+0x4d2967)

SUMMARY: ThreadSanitizer: data race teeworlds/src/engine/shared/jobs.h:35:30 in CJob::Status() const
==================
==================
WARNING: ThreadSanitizer: data race (pid=87358)
  Read of size 4 at 0x7b68000006c4 by main thread:
    #0 CJob::Result() const teeworlds/src/engine/shared/jobs.h:36:29 (teeworlds_srv+0x548961)
    #1 CMasterServer::Update() teeworlds/src/engine/shared/masterserver.cpp:79:43 (teeworlds_srv+0x5483c9)
    #2 CRegister::RegisterUpdate(int) teeworlds/src/engine/server/register.cpp:110:19 (teeworlds_srv+0x4c401b)
    #3 CServer::Run() teeworlds/src/engine/server/server.cpp:1442:15 (teeworlds_srv+0x4cf60c)
    #4 main teeworlds/src/engine/server/server.cpp:1942:21 (teeworlds_srv+0x4d3192)

  Previous write of size 4 at 0x7b68000006c4 by thread T1:
    #0 CJobPool::WorkerThread(void*) teeworlds/src/engine/shared/jobs.cpp:60:19 (teeworlds_srv+0x542ebe)
    #1 thread_run teeworlds/src/base/system.c:516:2 (teeworlds_srv+0x570b41)

  Location is heap block of size 1480 at 0x7b6800000600 allocated by main thread:
    #0 operator new(unsigned long) <null> (teeworlds_srv+0x4c2796)
    #1 CreateEngineMasterServer() teeworlds/src/engine/shared/masterserver.cpp:211:58 (teeworlds_srv+0x54755e)
    #2 main teeworlds/src/engine/server/server.cpp:1888:45 (teeworlds_srv+0x4d2a07)

  Thread T1 (tid=87361, running) created by main thread at:
    #0 pthread_create <null> (teeworlds_srv+0x45138b)
    #1 thread_init teeworlds/src/base/system.c:533:6 (teeworlds_srv+0x570aa9)
    #2 CEngine::CEngine(char const*) teeworlds/src/engine/shared/engine.cpp:67:13 (teeworlds_srv+0x53e74b)
    #3 CreateEngine(char const*) teeworlds/src/engine/shared/engine.cpp:176:58 (teeworlds_srv+0x53e54a)
    #4 main teeworlds/src/engine/server/server.cpp:1883:21 (teeworlds_srv+0x4d2967)

SUMMARY: ThreadSanitizer: data race teeworlds/src/engine/shared/jobs.h:36:29 in CJob::Result() const
==================
==================
WARNING: ThreadSanitizer: data race (pid=87358)
  Read of size 1 at 0x7b680000075c by main thread:
    #0 memcpy <null> (teeworlds_srv+0x45b44e)
    #1 CMasterServer::Update() teeworlds/src/engine/shared/masterserver.cpp:81:33 (teeworlds_srv+0x54841c)
    #2 CRegister::RegisterUpdate(int) teeworlds/src/engine/server/register.cpp:110:19 (teeworlds_srv+0x4c401b)
    #3 CServer::Run() teeworlds/src/engine/server/server.cpp:1442:15 (teeworlds_srv+0x4cf60c)
    #4 main teeworlds/src/engine/server/server.cpp:1942:21 (teeworlds_srv+0x4d3192)

  Previous write of size 1 at 0x7b680000075c by thread T1:
    #0 memset <null> (teeworlds_srv+0x45b129)
    #1 mem_zero teeworlds/src/base/system.c:309:2 (teeworlds_srv+0x5704a2)
    #2 CJobPool::WorkerThread(void*) teeworlds/src/engine/shared/jobs.cpp:60:21 (teeworlds_srv+0x542e9d)
    #3 thread_run teeworlds/src/base/system.c:516:2 (teeworlds_srv+0x570b41)

  Location is heap block of size 1480 at 0x7b6800000600 allocated by main thread:
    #0 operator new(unsigned long) <null> (teeworlds_srv+0x4c2796)
    #1 CreateEngineMasterServer() teeworlds/src/engine/shared/masterserver.cpp:211:58 (teeworlds_srv+0x54755e)
    #2 main teeworlds/src/engine/server/server.cpp:1888:45 (teeworlds_srv+0x4d2a07)

  Thread T1 (tid=87361, running) created by main thread at:
    #0 pthread_create <null> (teeworlds_srv+0x45138b)
    #1 thread_init teeworlds/src/base/system.c:533:6 (teeworlds_srv+0x570aa9)
    #2 CEngine::CEngine(char const*) teeworlds/src/engine/shared/engine.cpp:67:13 (teeworlds_srv+0x53e74b)
    #3 CreateEngine(char const*) teeworlds/src/engine/shared/engine.cpp:176:58 (teeworlds_srv+0x53e54a)
    #4 main teeworlds/src/engine/server/server.cpp:1883:21 (teeworlds_srv+0x4d2967)

SUMMARY: ThreadSanitizer: data race (teeworlds/build/teeworlds_srv+0x45b44e) in memcpy
==================

The issue occurs because there are volatile variables in CJob/CJobPool, however volatile does not imply atomic access.