[erlang-questions] Problem with binary_to_term on different machines

Sverker Eriksson <>
Fri Jan 20 17:45:26 CET 2017


Correction: Bug exists since OTP-17.0.

(and i tags R16B02_yielding_binary_to_term and 
OTP_R16B03_yielding_binary_to_term)

/Sverker


On 01/20/2017 05:17 PM, Sverker Eriksson wrote:
> This is indeed a problem in Erlang VM code (shallow copy of inflate 
> state)
> that has existed since R16B03, but not caused actual problem until 
> zlib v1.2.9.
>
> Fix coming up. Here is a preliminary patch for the impatient.
>
> diff --git a/erts/emulator/beam/external.c 
> b/erts/emulator/beam/external.c
> index beed847..1c4fff5 100644
> --- a/erts/emulator/beam/external.c
> +++ b/erts/emulator/beam/external.c
> @@ -1431,6 +1431,10 @@ static B2TContext* b2t_export_context(Process* 
> p, B2TContext* src)
>      if (ctx->state >= B2TDecode && ctx->u.dc.next == &src->u.dc.res) {
>          ctx->u.dc.next = &ctx->u.dc.res;
>      }
> +    else if (ctx->state == B2TUncompressChunk) {
> +        int cres = inflateCopy(&ctx->u.uc.stream, &src->u.uc.stream);
> +        ASSERT(cres == Z_OK); (void)cres;
> +    }
>      hp = HAlloc(p, PROC_BIN_SIZE);
>      ctx->trap_bin = erts_mk_magic_binary_term(&hp, &MSO(p), context_b);
>      return ctx;
>
>
> /Sverker, Erlang/OTP
>
>
> On 01/19/2017 04:14 AM, Michel Boaventura wrote:
>> Hi all,
>>
>> I've build erlang 19 from scratch on my gentoo machine but can't use
>> dialyzer, because it complains my beam files weren't compiled with
>> debug_info.
>>
>> I've read and debugged a log of dialyzer and erlang code and find out 
>> the
>> issue is that for some reason erlang can't parse the abstract part of 
>> the
>> files.
>>
>> To check this I save the abstract part on a file and tried to parse 
>> it on
>> my gentoo machine and on a Ubuntu server I have access. For some 
>> reason I
>> don't know it reads with no problem Ubuntu but gives me an invalid 
>> arg on
>> gentoo.
>>
>> I'm very new to erlang and have no clue of how to debug further. The 
>> binary
>> is attached and I'm reading it like:
>>
>> {ok, [Binary]} = file:consult("Abstr").
>> Term = binary_to_term(Binary).
>>
>> ps: I've sent a message similar to this one on this list, but since 
>> it was
>> my first one I think it wasn't accepted (and I do apologize for the 
>> double
>> post if you received it). But after it I've discovered the problem with
>> binary_to_term, so that message isn't so useful anyway.
>>
>>
>>
>> _______________________________________________
>> erlang-questions mailing list
>> 
>> http://erlang.org/mailman/listinfo/erlang-questions
>
>
>
>
> _______________________________________________
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> 
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