From b53f8a67649a371a38dc6d97b0dfe52111236a3e Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Tue, 1 Jun 2010 13:50:50 +0000 Subject: OTP-8658 Add missing memory barriers in erts_poll() Missing memory barriers in erts_poll() could cause the runtime system to hang indefinitely. --- erts/emulator/sys/common/erl_poll.c | 58 ++++++++++++++++++++++++++----------- 1 file changed, 41 insertions(+), 17 deletions(-) (limited to 'erts/emulator/sys/common') diff --git a/erts/emulator/sys/common/erl_poll.c b/erts/emulator/sys/common/erl_poll.c index d268547e1a..09fb6337f7 100644 --- a/erts/emulator/sys/common/erl_poll.c +++ b/erts/emulator/sys/common/erl_poll.c @@ -130,13 +130,18 @@ #define ERTS_POLLSET_IS_POLLED(PS) \ ((int) erts_smp_atomic_read(&(PS)->polled)) -#define ERTS_POLLSET_SET_POLLER_WOKEN_CHK(PS) \ - ((int) erts_smp_atomic_xchg(&(PS)->woken, (long) 1)) -#define ERTS_POLLSET_SET_POLLER_WOKEN(PS) \ - erts_smp_atomic_set(&(PS)->woken, (long) 1) -#define ERTS_POLLSET_UNSET_POLLER_WOKEN(PS) \ - erts_smp_atomic_set(&(PS)->woken, (long) 0) -#define ERTS_POLLSET_IS_POLLER_WOKEN(PS) \ +#define ERTS_POLLSET_SET_POLLER_WOKEN_CHK(PS) set_poller_woken_chk((PS)) +#define ERTS_POLLSET_SET_POLLER_WOKEN(PS) \ +do { \ + ERTS_THR_MEMORY_BARRIER; \ + erts_smp_atomic_set(&(PS)->woken, (long) 1); \ +} while (0) +#define ERTS_POLLSET_UNSET_POLLER_WOKEN(PS) \ +do { \ + erts_smp_atomic_set(&(PS)->woken, (long) 0); \ + ERTS_THR_MEMORY_BARRIER; \ +} while (0) +#define ERTS_POLLSET_IS_POLLER_WOKEN(PS) \ ((int) erts_smp_atomic_read(&(PS)->woken)) #else @@ -194,13 +199,18 @@ #else -#define ERTS_POLLSET_UNSET_INTERRUPTED_CHK(PS) \ - ((int) erts_smp_atomic_xchg(&(PS)->interrupt, (long) 0)) -#define ERTS_POLLSET_UNSET_INTERRUPTED(PS) \ - erts_smp_atomic_set(&(PS)->interrupt, (long) 0) -#define ERTS_POLLSET_SET_INTERRUPTED(PS) \ - erts_smp_atomic_set(&(PS)->interrupt, (long) 1) -#define ERTS_POLLSET_IS_INTERRUPTED(PS) \ +#define ERTS_POLLSET_UNSET_INTERRUPTED_CHK(PS) unset_interrupted_chk((PS)) +#define ERTS_POLLSET_UNSET_INTERRUPTED(PS) \ +do { \ + erts_smp_atomic_set(&(PS)->interrupt, (long) 0); \ + ERTS_THR_MEMORY_BARRIER; \ +} while (0) +#define ERTS_POLLSET_SET_INTERRUPTED(PS) \ +do { \ + ERTS_THR_MEMORY_BARRIER; \ + erts_smp_atomic_set(&(PS)->interrupt, (long) 1); \ +} while (0) +#define ERTS_POLLSET_IS_INTERRUPTED(PS) \ ((int) erts_smp_atomic_read(&(PS)->interrupt)) #endif @@ -336,16 +346,30 @@ struct ErtsPollSet_ { #endif }; -#if ERTS_POLL_ASYNC_INTERRUPT_SUPPORT && !defined(ERTS_SMP) - static ERTS_INLINE int unset_interrupted_chk(ErtsPollSet ps) { + int res; +#if ERTS_POLL_ASYNC_INTERRUPT_SUPPORT && !defined(ERTS_SMP) /* This operation isn't atomic, but we have no need at all for an atomic operation here... */ - int res = ps->interrupt; + res = ps->interrupt; ps->interrupt = 0; +#else + res = (int) erts_smp_atomic_xchg(&ps->interrupt, (long) 0); + ERTS_THR_MEMORY_BARRIER; +#endif return res; + +} + +#ifdef ERTS_SMP + +static ERTS_INLINE int +set_poller_woken_chk(ErtsPollSet ps) +{ + ERTS_THR_MEMORY_BARRIER; + return (int) erts_smp_atomic_xchg(&ps->woken, (long) 1); } #endif -- cgit v1.2.3