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Posted to dev@qpid.apache.org by "Ken Giusti (Jira)" <ji...@apache.org> on 2021/05/18 19:02:00 UTC

[jira] [Created] (DISPATCH-2130) python lock inversion deadlock

Ken Giusti created DISPATCH-2130:
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             Summary: python lock inversion deadlock
                 Key: DISPATCH-2130
                 URL: https://issues.apache.org/jira/browse/DISPATCH-2130
             Project: Qpid Dispatch
          Issue Type: Bug
          Components: Router Node
    Affects Versions: 1.16.0
            Reporter: Ken Giusti
            Assignee: Ken Giusti
             Fix For: 1.17.0


The python lock is a top-level lock: no other locks should be held when taking the python lock.

The python lock is held for as long as the thread is running in python.  The python code often calls back into C, which takes locks as necessary (timers, server lock, whatever).

Debug code should be added to enforce this.

TSAN deadlock trace:

21: Mutex M253 acquired here while holding mutex M13 in main thread: 
21: #0 pthread_mutex_lock <null> (libtsan.so.0+0x528ac) 
<M253 == timer lock == qd_server->lock> 
21: #1 sys_mutex_lock /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:57 (libqpid-dispatch.so+0xacee5) 
21: #2 qd_timer_schedule /home/kgiusti/work/dispatch/qpid-dispatch/src/timer.c:216 (libqpid-dispatch.so+0x1350fe) 
21: #3 qd_router_setup_late /home/kgiusti/work/dispatch/qpid-dispatch/src/router_node.c:2144 (libqpid-dispatch.so+0x128656) 
21: #4 ffi_call_unix64 <null> (libffi.so.6+0x6aef) 
21: #5 main_process /home/kgiusti/work/dispatch/qpid-dispatch/router/src/main.c:97 (qdrouterd+0x402697) 
21: #6 main /home/kgiusti/work/dispatch/qpid-dispatch/router/src/main.c:369 (qdrouterd+0x403557) 
21: 
21: Mutex M13 previously acquired by the same thread here: 
21: #0 pthread_mutex_lock <null> (libtsan.so.0+0x528ac) 
<M13 == python ilock> 
21: #1 sys_mutex_lock /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:57 (libqpid-dispatch.so+0xacee5) 
21: #2 qd_python_lock /home/kgiusti/work/dispatch/qpid-dispatch/src/python_embedded.c:902 (libqpid-dispatch.so+0xb070e) 
21: #3 qd_dispatch_load_config /home/kgiusti/work/dispatch/qpid-dispatch/src/dispatch.c:129 (libqpid-dispatch.so+0x80ad2) 
21: #4 main_process /home/kgiusti/work/dispatch/qpid-dispatch/router/src/main.c:97 (qdrouterd+0x402697) 
21: #5 main /home/kgiusti/work/dispatch/qpid-dispatch/router/src/main.c:369 (qdrouterd+0x403557) 
 
--------------------------- 
 
21: Mutex M13 acquired here while holding mutex M253 in thread T4: 
21: #0 pthread_mutex_lock <null> (libtsan.so.0+0x528ac) 
<M13 == python ilock> 
21: #1 sys_mutex_lock /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:57 (libqpid-dispatch.so+0xacee5) 
21: #2 qd_python_lock /home/kgiusti/work/dispatch/qpid-dispatch/src/python_embedded.c:902 (libqpid-dispatch.so+0xb070e) 
21: #3 qd_policy_socket_close /home/kgiusti/work/dispatch/qpid-dispatch/src/policy.c:296 (libqpid-dispatch.so+0xa3a8e) 
21: #4 qd_connection_free /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:925 (libqpid-dispatch.so+0x12f703) 
21: #5 thread_run /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:1127 (libqpid-dispatch.so+0x13069e) 
21: #6 _thread_init /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:172 (libqpid-dispatch.so+0xad37a) 
21: #7 <null> <null> (libtsan.so.0+0x2d33f) 
21: 
21: Mutex M253 previously acquired by the same thread here: 
21: #0 pthread_mutex_lock <null> (libtsan.so.0+0x528ac) 
<M253 == qd_server->lock> 
21: #1 sys_mutex_lock /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:57 (libqpid-dispatch.so+0xacee5) 
21: #2 qd_connection_free /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:920 (libqpid-dispatch.so+0x12f48f) 
21: #3 thread_run /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:1127 (libqpid-dispatch.so+0x13069e) 
21: #4 _thread_init /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:172 (libqpid-dispatch.so+0xad37a) 
21: #5 <null> <null> (libtsan.so.0+0x2d33f)



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