Re: [Caml-list] memory corruption using C stub

[Alexey Egorov <alex.only.d@gmail.com>]

Stack traces is not very helpful; it crashes at random places in OCaml code:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 4204.0xb4c]
0x0000000000414fac in camlSource__fun_6516 ()
(gdb)
(gdb) bt
#0  0x0000000000414fac in camlSource__fun_6516 ()
#1  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)


2017-06-10 20:40 GMT+05:00 Viet Le <vietlq85@gmail.com>:
> Do you have stack frame to look at?
>
>
> On Sat, 10 Jun 2017 at 16:33, Alexey Egorov <alex.only.d@gmail.com> wrote:
>>
>> Hello,
>>
>> I have an OCaml application with some C code which (I believe) is the
>> reason of some random crashes.
>>
>> Here is the code - https://pastebin.com/FVtLphZu
>> This function reads file at given offset, divides data into chunks and
>> compute checksums and compression ratio:
>>   external compute_data_props
>>     : string -> int -> int -> int -> (int * int * float) list =
>> "compute_data_props"
>>
>> The problem is, after some calls to this stub, application is crashing
>> at random places in OCaml code.
>> I can't figure out what's going wrong, but replacing this stub with
>> dummy function (which does nothing but returns some predefined list)
>> eliminates the problem.
>>
>> What can we do to debug it? We are using OCaml 4.04.1 and Windows 10,
>> and there is no other C stubs in our codebase.
>>
>> Thanks!
>>
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>
> --
> Kind regards,
> Viet