Buffer.contents causes Segmentation fault

[vicuna]

Original bug ID: 7003
Reporter: radekm
Assigned to: @damiendoligez
Status: closed (set by @damiendoligez on 2015-10-19T15:48:39Z)
Resolution: fixed
Priority: normal
Severity: major
Platform: 64-bit
OS: openSUSE
OS Version: 13.1
Version: 4.02.3
Target version: 4.03.0+dev / +beta1
Fixed in version: 4.03.0+dev / +beta1
Category: standard library
Monitored by: @gasche

Bug description

Following program

let _ =
let b = Buffer.create 7000_000_000 in
for i = 1 to 2500_000_000 do
Buffer.add_string b "a"
done;
print_endline "before";
let _ = Buffer.contents b in
print_endline "after"

produces

before
Segmentation fault

on my machine (I have 13.5 GB of free memory, 16 GB total, 18 GB total with swap).

Steps to reproduce

Constants 7000_000_000 and 2500_000_000 depend on the size of memory and they must be sufficiently large otherwise the program doesn't crash.

[vicuna]

Comment author: @damiendoligez

Reproduced on Mac OS X.

[vicuna]

Comment author: @damiendoligez

Fixed in rev 16525.