Binary corruption in binary construction

[dominicletz]

Describe the bug

When compiling the following code with any erlc from OTP 24.3.x (tested with 24.3.4.17) the resulting .beam file reports corrupted binary padding when executed on an x86_64 linux machine with either of OTP24/OTP25/OTP26/OTP27

To Reproduce

Save the attached erlang code as binary_error.erl and execute the corruption demo:

# Using OTP24 on linux x86_64
erlc binary_error.erl
# Using either of OTP24/25/26/27
erl -eval "binary_error:demo()"
Erlang/OTP 24 [erts-12.3.2.17] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [jit]

Eshell V12.3.2.17  (abort with ^G)
1> Error <<0,0,0,0,0,0,0,0,0,0,0,0,191,26,214,52,25,183,242,40,245,124,0,0,232,0,
        0,0,0,0,0,0>> != <<0,0,0,0,0,0,0,0,0,0,0,0,46,39,82,188,226,30,28,247,
                           217,209,255,170,91,199,135,225,44,86,233,52>>
...<snip>...
Done found 37 errors in 10000 iterations 

Using the same OTP24 pre compiled .beam file with OTP27 (27.0.1):

$ erl -eval "binary_error:demo()"
Erlang/OTP 27 [erts-15.0.1] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [jit:ns]

Error <<0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,50,85,9,16,144,126,0,0,128,0,0,0,0,0,0,
        0>> != <<0,0,0,0,0,0,0,0,0,0,0,0,103,31,112,17,76,235,1,188,119,220,82,
                 93,146,95,157,20,149,76,19,28>>
...<snip>...
Done found 63 errors in 10000 iterations 

Expected behavior

It is expected that the padding result of <<0:96/unsigned-integer, Hash:20/binary>> always retains the same 20 bytes of Hash as postfix.

Affected versions

Compiler of OTP24 (24.3.4.17) is causing this issue.
Runtimes of OTP24/25/26/27 are all affected if the compiled .beam file of OTP24 is used.

Additional context

binary_error.erl

-module(binary_error).
-export([demo/0]).

to_bytes32(Hash = <<_:160/unsigned-integer>>) ->
    <<0:96/unsigned-integer, Hash:20/binary>>.

prefix() ->
    <<0:96>>.

process() ->
    Bin = rand:bytes(20),
    Padded = to_bytes32(Bin),
    case Padded =:= <<(prefix())/binary, Bin/binary>> of
        false ->
            io:format("Error ~p != ~p~n", [Padded, <<(prefix())/binary, Bin/binary>>]),
            1;
        true ->
            0
    end.

demo() ->
    Iters = 10000,
    Errors = lists:sum([process() || _ <- lists:seq(1, Iters)]),
    io:format("Done found ~p errors in ~p iterations ~n", [Errors, Iters]).

[jhogberg]

Thanks for your report! OTP 24 is out of support, can you reproduce this with a file compiled with OTP 25 or later?