From 9e862df2bf26b9b1d79ba3b447945b7c0612e3d0 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Thu, 12 Jan 2017 18:12:38 +0100 Subject: erts: Add macro ERTS_PROC_LOCKS_HIGHER_THAN to safeguard against bugs due to future proc lock changes. The two places now using ERTS_PROC_LOCKS_HIGHER_THAN were kind of bugs as BTM and TRACE locks were missing. But there was probably no way to get there with BTM or TRACE locked. --- erts/emulator/beam/erl_message.c | 10 ++++++---- erts/emulator/beam/erl_process_lock.h | 4 ++++ 2 files changed, 10 insertions(+), 4 deletions(-) (limited to 'erts') diff --git a/erts/emulator/beam/erl_message.c b/erts/emulator/beam/erl_message.c index 118adc0c1b..04f9640a17 100644 --- a/erts/emulator/beam/erl_message.c +++ b/erts/emulator/beam/erl_message.c @@ -285,9 +285,11 @@ erts_queue_dist_message(Process *rcvr, if (!(rcvr_locks & ERTS_PROC_LOCK_MSGQ)) { if (erts_smp_proc_trylock(rcvr, ERTS_PROC_LOCK_MSGQ) == EBUSY) { ErtsProcLocks need_locks = ERTS_PROC_LOCK_MSGQ; - if (rcvr_locks & ERTS_PROC_LOCK_STATUS) { - erts_smp_proc_unlock(rcvr, ERTS_PROC_LOCK_STATUS); - need_locks |= ERTS_PROC_LOCK_STATUS; + ErtsProcLocks unlocks = + rcvr_locks & ERTS_PROC_LOCKS_HIGHER_THAN(ERTS_PROC_LOCK_MSGQ); + if (unlocks) { + erts_smp_proc_unlock(rcvr, unlocks); + need_locks |= unlocks; } erts_smp_proc_lock(rcvr, need_locks); } @@ -406,7 +408,7 @@ queue_messages(Process* receiver, if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT)) goto exiting; - need_locks = receiver_locks & (ERTS_PROC_LOCK_STATUS|ERTS_PROC_LOCK_TRACE); + need_locks = receiver_locks & ERTS_PROC_LOCKS_HIGHER_THAN(ERTS_PROC_LOCK_MSGQ); if (need_locks) { erts_smp_proc_unlock(receiver, need_locks); } diff --git a/erts/emulator/beam/erl_process_lock.h b/erts/emulator/beam/erl_process_lock.h index 2cccf0697a..e7d68f0a09 100644 --- a/erts/emulator/beam/erl_process_lock.h +++ b/erts/emulator/beam/erl_process_lock.h @@ -219,6 +219,10 @@ typedef struct erts_proc_lock_t_ { #define ERTS_PROC_LOCKS_ALL_MINOR (ERTS_PROC_LOCKS_ALL \ & ~ERTS_PROC_LOCK_MAIN) +/* All locks we first must unlock to lock L */ +#define ERTS_PROC_LOCKS_HIGHER_THAN(L) \ + (ERTS_PROC_LOCKS_ALL & (~(L) & ~((L)-1))) + #define ERTS_PIX_LOCKS_BITS 10 #define ERTS_NO_OF_PIX_LOCKS (1 << ERTS_PIX_LOCKS_BITS) -- cgit v1.2.3