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hio_write/hio_close are documented thread-safe, but they read io->ready/closed unlocked while the loop thread rewrites neighbouring bits of the same bitfield word, and hio_write stamps last_write_hrtime from the loop's cur_hrtime. Make those fields atomic, and make loop->status atomic, stored before hloop_stop's wakeup so the woken loop sees STOP. Found with ThreadSanitizer.
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Fixes data races reported by ThreadSanitizer when
hio_write/hio_closeare called from a non-loop thread (both are documented as thread-safe).Changes
hio_s:ready,connected,closedare nowatomic_boolinstead of bitfield bits. They are read without a lock from other threads, while the loop thread rewrites neighbouring bits in the same word.hio_s:last_read_hrtime/last_write_hrtimeandhloop_s::cur_hrtimeare nowatomic_ullong, sincehio_writestampslast_write_hrtimefromcur_hrtimeon the caller's thread.hloop_s::statusis nowatomic_int.hloop_runstoresRUNNINGafter settingpid/tid, sohloop_stopsees a validtid.hloop_stopsetsSTOP(via newhatomic_exchange) before the wakeup. Before, the loop could wake, still seeRUNNING, and block again.base/hatomic.h: addATOMIC_EXCHANGE/hatomic_exchangefor C11, C++, GCC__sync, Win32 and a non-atomic fallback.sizeof(struct hio_s)grows from 424 to 432 on linux-x64.