17/12/2021 19:29, Stephen Hemminger: > If DPDK is built with thread sanitizer it reports a race > in setting of multiprocess file descriptor. The fix is to > use atomic operations when updating mp_fd.
Please could explain more the condition of the race? Is it between init and cleanup of the same file descriptor? How atomic is helping here? > > Simple example: > $ dpdk-testpmd -l 1-3 --no-huge > ... > EAL: Error - exiting with code: 1 > Cause: Creation of mbuf pool for socket 0 failed: Cannot allocate memory > ================== > WARNING: ThreadSanitizer: data race (pid=83054) > Write of size 4 at 0x55e3b7fce450 by main thread: > #0 rte_mp_channel_cleanup <null> (dpdk-testpmd+0x160d79c) > #1 rte_eal_cleanup <null> (dpdk-testpmd+0x1614fb5) > #2 rte_exit <null> (dpdk-testpmd+0x15ec97a) > #3 mbuf_pool_create.cold <null> (dpdk-testpmd+0x242e1a) > #4 main <null> (dpdk-testpmd+0x5ab05d) > > Previous read of size 4 at 0x55e3b7fce450 by thread T2: > #0 mp_handle <null> (dpdk-testpmd+0x160c979) > #1 ctrl_thread_init <null> (dpdk-testpmd+0x15ff76e) > > As if synchronized via sleep: > #0 nanosleep > ../../../../src/libsanitizer/tsan/tsan_interceptors_posix.cpp:362 > (libtsan.so.0+0x5cd8e) > #1 get_tsc_freq <null> (dpdk-testpmd+0x1622889) > #2 set_tsc_freq <null> (dpdk-testpmd+0x15ffb9c) > #3 rte_eal_timer_init <null> (dpdk-testpmd+0x1622a34) > #4 rte_eal_init.cold <null> (dpdk-testpmd+0x26b314) > #5 main <null> (dpdk-testpmd+0x5aab45) > > Location is global 'mp_fd' of size 4 at 0x55e3b7fce450 > (dpdk-testpmd+0x0000027c7450) > > Thread T2 'rte_mp_handle' (tid=83057, running) created by main thread at: > #0 pthread_create > ../../../../src/libsanitizer/tsan/tsan_interceptors_posix.cpp:962 > (libtsan.so.0+0x58ba2) > #1 rte_ctrl_thread_create <null> (dpdk-testpmd+0x15ff870) > #2 rte_mp_channel_init.cold <null> (dpdk-testpmd+0x269986) > #3 rte_eal_init <null> (dpdk-testpmd+0x1615b28) > #4 main <null> (dpdk-testpmd+0x5aab45)
