[DISPATCH-2135] data race accessing Q2 holdoff state

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.16.0
• Fix Version/s: 1.20.0
• Component/s: Router Node
• Labels: race-condition tsan
• Assignee: Ken Giusti
• Reporter: Ken Giusti
• Created: 18/May/21 20:42
• Updated: 15/Mar/22 21:54

Description

qd_message_Q2_holdoff_disable() modifies the disable_q2_holdoff flag without holding the message content lock.  In the below trace the holdoff is being disabled by the timer thread while being read by an I/O thread:

 

74: WARNING: ThreadSanitizer: data race (pid=643055)
74: Write of size 1 at 0x7b64000658b5 by thread T2:
74: #0 qd_message_Q2_holdoff_disable /home/kgiusti/work/dispatch/qpid-dispatch/src/message.c:2876 (libqpid-dispatch.so+0x9a2bc)
74: #1 qdr_tcp_deliver /home/kgiusti/work/dispatch/qpid-dispatch/src/adaptors/tcp_adaptor.c:1405 (libqpid-dispatch.so+0x65f91)
74: #2 qdr_link_process_deliveries /home/kgiusti/work/dispatch/qpid-dispatch/src/router_core/transfer.c:178 (libqpid-dispatch.so+0x1045c6)
74: #3 qdr_tcp_push /home/kgiusti/work/dispatch/qpid-dispatch/src/adaptors/tcp_adaptor.c:1392 (libqpid-dispatch.so+0x65e9b)
74: #4 qdr_connection_process /home/kgiusti/work/dispatch/qpid-dispatch/src/router_core/connections.c:414 (libqpid-dispatch.so+0xc4bec)
74: #5 on_activate /home/kgiusti/work/dispatch/qpid-dispatch/src/adaptors/tcp_adaptor.c:155 (libqpid-dispatch.so+0x5e251)
74: #6 qd_timer_visit /home/kgiusti/work/dispatch/qpid-dispatch/src/timer.c:317 (libqpid-dispatch.so+0x135b52)
74: #7 handle /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:1006 (libqpid-dispatch.so+0x12fc8d)
74: #8 thread_run /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:1121 (libqpid-dispatch.so+0x13063a)
74: #9 _thread_init /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:172 (libqpid-dispatch.so+0xad37a)
74: #10 <null> <null> (libtsan.so.0+0x2d33f)
74:
74: Previous read of size 1 at 0x7b64000658b5 by thread T3 (mutexes: write M2644):
74: #0 qd_message_Q2_holdoff_should_block /home/kgiusti/work/dispatch/qpid-dispatch/src/message.c:2885 (libqpid-dispatch.so+0x9a327)
74: #1 qd_message_extend /home/kgiusti/work/dispatch/qpid-dispatch/src/message.c:2400 (libqpid-dispatch.so+0x97eda)
74: #2 qd_message_stream_data_append /home/kgiusti/work/dispatch/qpid-dispatch/src/message.c:2965 (libqpid-dispatch.so+0x9a7ae)
74: #3 handle_incoming /home/kgiusti/work/dispatch/qpid-dispatch/src/adaptors/tcp_adaptor.c:393 (libqpid-dispatch.so+0x5fb17)
74: #4 handle_connection_event /home/kgiusti/work/dispatch/qpid-dispatch/src/adaptors/tcp_adaptor.c:850 (libqpid-dispatch.so+0x6232c)
74: #5 handle_event_with_context /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:802 (libqpid-dispatch.so+0x12ecb6)
74: #6 do_handle_raw_connection_event /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:808 (libqpid-dispatch.so+0x12ed08)
74: #7 handle /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:1089 (libqpid-dispatch.so+0x1304e6)
74: #8 thread_run /home/kgiusti/work/dispatch/qpid-dispatch/src/server.c:1121 (libqpid-dispatch.so+0x13063a)
74: #9 _thread_init /home/kgiusti/work/dispatch/qpid-dispatch/src/posix/threading.c:172 (libqpid-dispatch.so+0xad37a)
74: #10 <null> <null> (libtsan.so.0+0x2d33f)