Segfault with Erlang otp #2

README.md

Case2 Binary Construction

• Segfault when constructing a binary like this (<<A/binary, B/binary>>)
• Code to reproduce this issue

    # Arguments might need to be changed according to executing environments
    erl -noshell -run case2 main 134217728 2147483648 192

• Env

  name | value :----- |:----- cpu |32core memory |32G uname |Linux * 2.6.32-358.6.2.el6.x86_64 #1 SMP Thu May 16 20:59:36 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux Erlang |15B03,16B02,16B03

backtrace

(gdb) bt
#0  0x00007f7bc511ec31 in memcpy () from /lib64/libc.so.6
#1  0x00000000004fbcc0 in erts_new_bs_put_binary_all (EBS=0x4a16958, 
    arg=<value optimized out>, unit=<value optimized out>)
    at beam/erl_bits.c:994
#2  0x0000000000530558 in process_main ()
    at x86_64-unknown-linux-gnu/opt/smp/beam_cold.h:209
#3  0x0000000000491ca9 in sched_thread_func (vesdp=0x4a16940)
    at beam/erl_process.c:5801
#4  0x000000000059b956 in thr_wrapper (vtwd=0x7fff042f7cc0)
    at pthread/ethread.c:106
#5  0x00007f7bc5637851 in start_thread () from /lib64/libpthread.so.0
#6  0x00007f7bc517d90d in clone () from /lib64/libc.so.6

case2.erl

%% -*- mode: erlang;erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ft=erlang ts=4 sw=4 et
-module(case2).
-export([main/1]).

-define(TEST_FILE_PATH,       "test.dat").

main([Arg1,Arg2,Arg3|_T]) ->
    FileSize = list_to_integer(Arg1),
    ReadBytes = list_to_integer(Arg2),
    NumRepeat = list_to_integer(Arg3),
    %% generate a test file
    Data = crypto:rand_bytes(FileSize),
    file:write_file(?TEST_FILE_PATH, Data),
    {ok, IoDev} = file:open(?TEST_FILE_PATH, [read, raw, binary]),
    try
        Ret = random_read(IoDev, FileSize, ReadBytes, NumRepeat, <<>>),
        io:format(user, "[info]ret size:~p~n", [size(Ret)])
    catch
        Class:Reason ->
            io:format(user, "[error]class:~p reason:~p stacktrace:~p~n",[Class, Reason, erlang:get_stacktrace()])
    after
        file:close(IoDev)
    end,
    ok;
main(_) ->
    io:format(user, "Usage: case2 (file size) (read bytes) (# of operations)~n", []).

random_read(_, _, _, 0, Acc) -> Acc;
random_read(IoDev, FileSize, MaxReadBytes, N, Acc) ->
    Offset = random:uniform(FileSize - 1),
    ReadBytes = random:uniform(round(MaxReadBytes/2)) + round(MaxReadBytes/2),
    NewAcc = case file:pread(IoDev, Offset, ReadBytes) of
        {ok, Data} -> 
            <<Acc/binary, Data/binary>>;
        eof -> 
            Acc;
        {error, Reason} -> 
            io:format(user, "[error] file read error:~p~n", [Reason]),
            exit(Reason)
    end,
    NewAcc2 = case N rem 8 of
        0 -> 
            io:format(user, "[info] memory usages:~p~n", [erlang:memory()]),
            io:format(user, "[info] acc size:~p~n", [size(NewAcc)]),
            <<Clipped:128/binary, _/binary>> = NewAcc,
            Clipped;
        _ -> NewAcc
    end,
    random_read(IoDev, FileSize, MaxReadBytes, N - 1, NewAcc2).