diff options
| -rw-r--r-- | erts/emulator/beam/beam_emu.c | 1 | ||||
| -rw-r--r-- | erts/emulator/beam/erl_message.h | 16 | ||||
| -rw-r--r-- | erts/emulator/beam/msg_instrs.tab | 21 | ||||
| -rw-r--r-- | erts/emulator/beam/ops.tab | 7 | ||||
| -rw-r--r-- | erts/emulator/test/receive_SUITE.erl | 62 |
5 files changed, 85 insertions, 22 deletions
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index bc95ccec52..ef9abcde08 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -1454,6 +1454,7 @@ handle_error(Process* c_p, BeamInstr* pc, Eterm* reg, ErtsCodeMFA *bif_mfa) reg[3] = c_p->ftrace; if ((new_pc = next_catch(c_p, reg))) { c_p->cp = 0; /* To avoid keeping stale references. */ + c_p->msg.saved_last = 0; /* No longer safe to use this position */ return new_pc; } if (c_p->catches > 0) erts_exit(ERTS_ERROR_EXIT, "Catch not found"); diff --git a/erts/emulator/beam/erl_message.h b/erts/emulator/beam/erl_message.h index 9c8cf84e43..a14f4f51d8 100644 --- a/erts/emulator/beam/erl_message.h +++ b/erts/emulator/beam/erl_message.h @@ -167,10 +167,9 @@ typedef struct { Sint len; /* queue length */ /* - * The following two fields are used by the recv_mark/1 and + * The following field is used by the recv_mark/1 and * recv_set/1 instructions. */ - BeamInstr* mark; /* address to rec_loop/2 instruction */ ErtsMessage** saved_last; /* saved last pointer */ } ErlMessageQueue; @@ -236,12 +235,17 @@ typedef struct erl_trace_message_queue__ { (p)->msg.len--; \ if (__mp == NULL) \ (p)->msg.last = (p)->msg.save; \ - (p)->msg.mark = 0; \ } while(0) -/* Reset message save point (after receive match) */ -#define JOIN_MESSAGE(p) \ - (p)->msg.save = &(p)->msg.first +/* + * Reset message save point (after receive match). + * Also invalidate the saved position since it may no + * longer be safe to use. + */ +#define JOIN_MESSAGE(p) do { \ + (p)->msg.save = &(p)->msg.first; \ + (p)->msg.saved_last = 0; \ +} while(0) /* Save current message */ #define SAVE_MESSAGE(p) \ diff --git a/erts/emulator/beam/msg_instrs.tab b/erts/emulator/beam/msg_instrs.tab index 8055a8616f..d6d4d2fb49 100644 --- a/erts/emulator/beam/msg_instrs.tab +++ b/erts/emulator/beam/msg_instrs.tab @@ -43,27 +43,23 @@ // * // */ -recv_mark(Dest) { +i_recv_mark() { /* - * Save the current position in message buffer and the - * the label for the loop_rec/2 instruction for the - * the receive statement. + * Save the current position in message buffer. */ - $SET_REL_I(c_p->msg.mark, $Dest); c_p->msg.saved_last = c_p->msg.last; } i_recv_set() { /* - * If the mark is valid (points to the loop_rec/2 - * instruction that follows), we know that the saved - * position points to the first message that could - * possibly be matched out. + * If c_p->msg.saved_last is non-zero, it points to the first + * message that could possibly be matched out. * - * If the mark is invalid, we do nothing, meaning that - * we will look through all messages in the message queue. + * If c_p->msg.saved_last is zero, it means that it was invalidated + * because another receive was executed before this i_recv_set() + * instruction was reached. */ - if (c_p->msg.mark == (BeamInstr *) ($NEXT_INSTRUCTION)) { + if (c_p->msg.saved_last) { c_p->msg.save = c_p->msg.saved_last; } SET_I($NEXT_INSTRUCTION); @@ -131,6 +127,7 @@ i_loop_rec(Dest) { ASSERT(HTOP == c_p->htop && E == c_p->stop); /* TODO: Add DTrace probe for this bad message situation? */ UNLINK_MESSAGE(c_p, msgp); + c_p->msg.saved_last = 0; /* Better safe than sorry. */ msgp->next = NULL; erts_cleanup_messages(msgp); goto loop_rec__; diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab index a560bde920..3df91056cb 100644 --- a/erts/emulator/beam/ops.tab +++ b/erts/emulator/beam/ops.tab @@ -1565,7 +1565,12 @@ on_load # # R14A. # -recv_mark f +# Modified in OTP 21 because it turns out that we don't need the +# label after all. +# + +recv_mark f => i_recv_mark +i_recv_mark recv_set Fail | label Lbl | loop_rec Lf Reg => \ i_recv_set | label Lbl | loop_rec Lf Reg diff --git a/erts/emulator/test/receive_SUITE.erl b/erts/emulator/test/receive_SUITE.erl index a12019ec83..1fe11428b4 100644 --- a/erts/emulator/test/receive_SUITE.erl +++ b/erts/emulator/test/receive_SUITE.erl @@ -25,14 +25,16 @@ -include_lib("common_test/include/ct.hrl"). -export([all/0, suite/0, - call_with_huge_message_queue/1,receive_in_between/1]). + call_with_huge_message_queue/1,receive_in_between/1, + receive_opt_exception/1,receive_opt_recursion/1]). suite() -> [{ct_hooks,[ts_install_cth]}, {timetrap, {minutes, 3}}]. -all() -> - [call_with_huge_message_queue, receive_in_between]. +all() -> + [call_with_huge_message_queue, receive_in_between, + receive_opt_exception, receive_opt_recursion]. call_with_huge_message_queue(Config) when is_list(Config) -> Pid = spawn_link(fun echo_loop/0), @@ -113,6 +115,60 @@ receive_one() -> dummy -> ok end. +receive_opt_exception(_Config) -> + Recurse = fun() -> + %% Overwrite with the same mark, + %% and never consume it. + ThrowFun = fun() -> throw(aborted) end, + aborted = (catch do_receive_opt_exception(ThrowFun)), + ok + end, + do_receive_opt_exception(Recurse), + + %% Eat the second message. + receive + Ref when is_reference(Ref) -> ok + end. + +do_receive_opt_exception(Disturber) -> + %% Create a receive mark. + Ref = make_ref(), + self() ! Ref, + Disturber(), + receive + Ref -> + ok + after 0 -> + error(the_expected_message_was_not_there) + end. + +receive_opt_recursion(_Config) -> + Recurse = fun() -> + %% Overwrite with the same mark, + %% and never consume it. + NoOp = fun() -> ok end, + BlackHole = spawn(NoOp), + expected = do_receive_opt_recursion(BlackHole, NoOp, true), + ok + end, + do_receive_opt_recursion(self(), Recurse, false), + ok. + +do_receive_opt_recursion(Recipient, Disturber, IsInner) -> + Ref = make_ref(), + Recipient ! Ref, + Disturber(), + receive + Ref -> ok + after 0 -> + case IsInner of + true -> + expected; + false -> + error(the_expected_message_was_not_there) + end + end. + %%% %%% Common helpers. %%% |