From 4458257e5c9c48d43fa0ea4fa981436f364e14e2 Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Wed, 6 Apr 2011 09:53:04 +0200 Subject: Only set status P_WAITING when needed The status of a process was unnecessarily set to waiting before the process was enqueued in a run queue. This bug was harmless up until OTP-R14B01. In OTP-R14B02 erlang:hibernate/3 was fixed (OTP-9125). After the introduction of OTP-9125, the previously harmless process status bug sometimes caused erroneous badarg exceptions from process_info(). --- erts/emulator/beam/beam_emu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'erts/emulator/beam/beam_emu.c') diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index 7b2aac0908..df9d067727 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -6276,12 +6276,13 @@ erts_hibernate(Process* c_p, Eterm module, Eterm function, Eterm args, Eterm* re PROCESS_MAIN_CHK_LOCKS(c_p); erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS); ASSERT(!ERTS_PROC_IS_EXITING(c_p)); - c_p->status = P_WAITING; #ifdef ERTS_SMP ERTS_SMP_MSGQ_MV_INQ2PRIVQ(c_p); if (c_p->msg.len > 0) erts_add_to_runq(c_p); + else #endif + c_p->status = P_WAITING; } erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS); c_p->current = bif_export[BIF_hibernate_3]->code; -- cgit v1.2.3 From b7ecdcd1ae9e11b8f75e11b82d94da32837932bc Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Thu, 7 Apr 2011 11:54:37 +0200 Subject: Fix thread unsafe access Fix thread unsafe access to process status field introduced in OTP-9125. --- erts/emulator/beam/beam_emu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'erts/emulator/beam/beam_emu.c') diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index df9d067727..47bff4a427 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -3419,7 +3419,8 @@ void process_main(void) r(0) = c_p->def_arg_reg[0]; x(1) = c_p->def_arg_reg[1]; x(2) = c_p->def_arg_reg[2]; - if (c_p->status == P_WAITING) { + if (c_p->flags & F_HIBERNATE_SCHED) { + c_p->flags &= ~F_HIBERNATE_SCHED; goto do_schedule; } Dispatch(); @@ -5224,6 +5225,7 @@ void process_main(void) OpCase(i_hibernate): { SWAPOUT; if (erts_hibernate(c_p, r(0), x(1), x(2), reg)) { + c_p->flags &= ~F_HIBERNATE_SCHED; goto do_schedule; } else { I = handle_error(c_p, I, reg, hibernate_3); @@ -6286,6 +6288,7 @@ erts_hibernate(Process* c_p, Eterm module, Eterm function, Eterm args, Eterm* re } erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MSGQ|ERTS_PROC_LOCK_STATUS); c_p->current = bif_export[BIF_hibernate_3]->code; + c_p->flags |= F_HIBERNATE_SCHED; /* Needed also when woken! */ return 1; } -- cgit v1.2.3