From b2f7b51f420a233a41c885d8b44919d88f1e7ba5 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Wed, 14 Jun 2017 11:57:13 +0200 Subject: erts: Must have main lock when flushing trace messages If we don't have the main lock, multiple threads may come in and do the flush at the same time which will lead to all kinds of strang problems. --- erts/emulator/beam/erl_nif.c | 4 ++++ erts/emulator/beam/erl_process.c | 18 +++++++++--------- 2 files changed, 13 insertions(+), 9 deletions(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c index 4815e5e7bb..8ed429b214 100644 --- a/erts/emulator/beam/erl_nif.c +++ b/erts/emulator/beam/erl_nif.c @@ -588,6 +588,10 @@ int erts_flush_trace_messages(Process *c_p, ErtsProcLocks c_p_locks) ErlTraceMessageQueue *msgq, **last_msgq; int reds = 0; + /* Only one thread at a time is allowed to flush trace messages, + so we require the main lock to be held when doing the flush */ + ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(c_p); + erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_TRACE); msgq = c_p->trace_msg_q; diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c index fc2b34e70f..0ff9484daf 100644 --- a/erts/emulator/beam/erl_process.c +++ b/erts/emulator/beam/erl_process.c @@ -11768,9 +11768,11 @@ flush_dirty_trace_messages(void *vpid) erts_free(ERTS_ALC_T_DIRTY_SL, vpid); #endif - proc = erts_proc_lookup(pid); - if (proc) - (void) erts_flush_trace_messages(proc, 0); + proc = erts_pid2proc_opt(NULL, 0, pid, ERTS_PROC_LOCK_MAIN, 0); + if (proc) { + (void) erts_flush_trace_messages(proc, ERTS_PROC_LOCK_MAIN); + erts_smp_proc_unlock(proc, ERTS_PROC_LOCK_MAIN); + } } #endif /* ERTS_DIRTY_SCHEDULERS */ @@ -14102,8 +14104,11 @@ erts_continue_exit_process(Process *p) have none here */ } + erts_smp_proc_lock(p, ERTS_PROC_LOCK_MAIN); + ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p); + #ifdef ERTS_SMP - erts_flush_trace_messages(p, 0); + erts_flush_trace_messages(p, ERTS_PROC_LOCK_MAIN); #endif ERTS_TRACER_CLEAR(&ERTS_TRACER(p)); @@ -14111,11 +14116,6 @@ erts_continue_exit_process(Process *p) if (!delay_del_proc) delete_process(p); -#ifdef ERTS_SMP - erts_smp_proc_lock(p, ERTS_PROC_LOCK_MAIN); - ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p); -#endif - return; yield: -- cgit v1.2.3