process_info/2 doesn't report some large appended binaries. #6573
Description
Describe the bug
process_info/2 doesn't report some large appended binaries. This behavior seems to be dependent on the size of the first binary in the append.
There is also a difference sometimes between calling process_info for self process vs another process. Where calling process_info for self usually has more chance of getting results.
To Reproduce
Compile this module
-module(bin_test).
-behaviour(gen_server).
-export([init/1, handle_call/3, handle_cast/2, test/1]).
init(_) ->
{ok, #{bin => ""}}.
handle_call({add_binary, Size}, _, State) ->
RandomBytes = crypto:strong_rand_bytes(Size),
Bin = <<RandomBytes/binary, "a">>,
NewState = maps:put(bin, Bin, State),
timer:sleep(200 + rand:uniform(1000)), % To rule out internal racing
check_binaries(self, Size, self()),
{reply, ok, NewState}.
handle_cast(_, S) ->
{noreply, S}.
test(From) ->
{ok, Pid} = gen_server:start_link(?MODULE, nil, []),
To = From + 16,
lists:foreach(fun(Size) ->
gen_server:call(Pid, {add_binary, Size}),
check_binaries(other, Size, Pid)
end, lists:seq(From, To)).
check_binaries(From, Size, Pid) ->
{binary, Bins} = process_info(Pid, binary),
% remove small bins, these are used to call io:fwrite/2
Bins = lists:filter(fun({_, BinSize, _}) -> BinSize > 100 end, Bins),
case Bins of
[] -> io:fwrite("~p~n", [[From, Size, "emtpy!"]]);
Bins -> io:fwrite("~p~n", [[From, Size, Bins]])
end.then run
bin_test:test(1024 * 1024 * 1024).On my machine I get these results (consistently)
[self,1073741824,"emtpy!"]
[other,1073741824,"emtpy!"]
[self,1073741825,[{6730649640,1073741825,1}]]
[other,1073741825,[{6730649640,1073741825,1}]]
[self,1073741826,[{10381389864,1073741826,1}]]
[other,1073741826,[{10381389864,1073741826,1}]]
[self,1073741827,"emtpy!"]
[other,1073741827,"emtpy!"]
[self,1073741828,[{10381389864,1073741828,1}]]
[other,1073741828,"emtpy!"]
[self,1073741829,"emtpy!"]
[other,1073741829,"emtpy!"]
[self,1073741830,"emtpy!"]
[other,1073741830,"emtpy!"]
[self,1073741831,"emtpy!"]
[other,1073741831,"emtpy!"]
[self,1073741832,[{15105876008,1073741832,1}]]
[other,1073741832,"emtpy!"]
[self,1073741833,[{15105876008,1073741833,1}]]
[other,1073741833,"emtpy!"]
[self,1073741834,[{15105876008,1073741834,1}]]
[other,1073741834,[{15105876008,1073741834,1}]]
[self,1073741835,[{15105876008,1073741835,1}]]
[other,1073741835,[{15105876008,1073741835,1}]]
[self,1073741836,[{6730649640,1073741836,1}]]
[other,1073741836,[{6730649640,1073741836,1}]]
[self,1073741837,[{10381389864,1073741837,1}]]
[other,1073741837,[{10381389864,1073741837,1}]]
[self,1073741838,[{6730649640,1073741838,1}]]
[other,1073741838,[{6730649640,1073741838,1}]]
[self,1073741839,[{10381389864,1073741839,1}]]
[other,1073741839,[{10381389864,1073741839,1}]]
[self,1073741840,[{6730649640,1073741840,1}]]
[other,1073741840,[{6730649640,1073741840,1}]]
This line triggers the issue:
Bin = <<RandomBytes/binary, "a">>,
Replacing it with just
Bin = RandomBytes/binary,
does work as expected.
Expected behavior
To see at least the currently referenced large binaries reported.
Affected versions
Erlang/OTP 25 [erts-13.1.1] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [jit:ns] [dtrace]
I have seen this issue on older versions too.
Additional context
Running on an Intel Mac with macOS 12.6.