Original bug ID: 3612
Reporter: administrator
Assigned to: @gasche
Status: closed (set by @xavierleroy on 2017-02-16T14:15:01Z)
Resolution: fixed
Priority: high
Severity: major
Target version: 4.03.0+dev / +beta1
Fixed in version: 4.03.0+dev / +beta1
Category: otherlibs
Monitored by: till @oandrieu @mmottl

Bug description

Full_Name: Gary Huber
Version: 3.08.3
OS: Red Hat 8.0
Submission from: machaut.ucsd.edu (132.239.25.28)

Dear Ocaml folks,

I think I may have discovered a memory leak when reading
Bigarray objects from a file.
I use the first program to generate a file, which is read by the
second program. When I run the second program using the
memory leak checker valgrind, it shows some leaks.

By the way, I love Ocaml - I abandoned C++ over 2 years
ago for Ocaml. Thanks for developing such a great language.

(* First program: bug_gen.ml *)

type vector = (float, Bigarray.float64_elt, Bigarray.c_layout)
Bigarray.Array1.t
let ndim = 8;;

let x = Bigarray.Array1.create Bigarray.float64 Bigarray.c_layout ndim;;
for k = 0 to ndim-1 do
Bigarray.Array1.set x k 11.1
done;;

let n = 10000;;

let fp = open_out_bin "stuff.dat";;

output_value fp n;;
for i = 0 to n-1 do
output_value fp x
done;;

(* Second program: bug.ml *)

type vector = (float, Bigarray.float64_elt, Bigarray.c_layout)
Bigarray.Array1.t
let fp = open_in_bin "stuff.dat";;

let n = ((input_value fp) : int);;

for i = 0 to n-1 do
let v = ((input_value fp):vector) in ()
done
;;

close_in fp;;

Output from valgrind:

valgrind --leak-check=yes ./bug
==18183== Memcheck, a.k.a. Valgrind, a memory error detector for x86-linux.
==18183== Copyright (C) 2002-2003, and GNU GPL'd, by Julian Seward.
==18183== Using valgrind-2.0.0, a program supervision framework for x86-linux.
==18183== Copyright (C) 2000-2003, and GNU GPL'd, by Julian Seward.
==18183== Estimated CPU clock rate is 1499 MHz
==18183== For more details, rerun with: -v
==18183==
==18183==
==18183== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
==18183== malloc/free: in use at exit: 1065285 bytes in 10016 blocks.==18183==
malloc/free: 30018 allocs, 20002 frees, 1975298 bytes allocated.
==18183== For counts of detected errors, rerun with: -v
==18183== searching for pointers to 10016 not-freed blocks.
==18183== checked 4578268 bytes.
==18183==
==18183== 60 bytes in 1 blocks are definitely lost in loss record 1 of 7
==18183== at 0x400296B2: malloc (vg_replace_malloc.c:153)
==18183== by 0x804ECDE: caml_init_major_heap (in /home/ghuber/hcmm/flip/bug)
==18183== by 0x805653D: caml_init_gc (in /home/ghuber/hcmm/flip/bug)
==18183== by 0x8058F6C: caml_main (in /home/ghuber/hcmm/flip/bug)
==18183==
==18183==
==18183== 1088 bytes in 17 blocks are possibly lost in loss record 2
of 7
==18183== at 0x400296B2: malloc (vg_replace_malloc.c:153)
==18183== by 0x804D124: bigarray_deserialize (bigarray_stubs.c:785)
==18183== by 0x8054AA8: intern_rec (in /home/ghuber/hcmm/flip/bug)==18183==
by 0x8054D82: caml_input_val (in /home/ghuber/hcmm/flip/bug)
==18183==
==18183==
==18183== 339392 bytes in 5303 blocks are definitely lost in loss record 7 of 7
==18183== at 0x400296B2: malloc (vg_replace_malloc.c:153)
==18183== by 0x804D124: bigarray_deserialize (bigarray_stubs.c:785)
==18183== by 0x8054AA8: intern_rec (in /home/ghuber/hcmm/flip/bug)==18183==
by 0x8054D82: caml_input_val (in /home/ghuber/hcmm/flip/bug)
==18183==
==18183== LEAK SUMMARY:
==18183== definitely lost: 339452 bytes in 5304 blocks.
==18183== possibly lost: 1088 bytes in 17 blocks.
==18183== still reachable: 724745 bytes in 4695 blocks.
==18183== suppressed: 0 bytes in 0 blocks.
==18183== Reachable blocks (those to which a pointer was found) are not shown.
==18183== To see them, rerun with: --show-reachable=yes
==18183==