bug#20079: Fwd: Memory leak from seek/ftell with files larger than 2GB

[Anand Mohanadoss <anand108@gmail.com>]

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Hi Andy,

Thanks a lot for the fix!

Anand

On Thu, Jun 23, 2016 at 6:31 PM, Andy Wingo <wingo@pobox.com> wrote:

> Hi,
>
> Thank you very much for this one!  Turns out we had an incredibly
> embarrassing bug in which we forgot to attach finalizers for bignums
> created by scm_from_{uint64,int64} on 32-bit platforms.  Fixed in master
> and stable-2.0.
>
> Cheers,
>
> Andy
>
> On Wed 11 Mar 2015 13:38, Anand Mohanadoss <anand108@gmail.com> writes:
>
> > Hi,
> >
> > I had sent the following to the user forum and did not receive any
> > comments. I am reposting it in the bug forum with the hope that one of
> > the experts may be able to comment...
> >
> > Thanks,
> > Anand
> >
> > ---------- Forwarded message ----------
> > From: Anand Mohanadoss <anand108@gmail.com>
> > Date: Wed, Feb 25, 2015 at 9:35 PM
> > Subject: Memory leak from seek/ftell with files larger than 2GB
> > To: guile-user@gnu.org
> >
> > Hi,
> >
> > We are seeing an issue with seek and ftell leaking memory with files
> > larger than 2GB.
> >
> > We are using 2.0.11 guile built as a 32-bit application with large
> > file support enabled (guile was built using gcc 4.4.0 for Linux with
> > flags _FILE_OFFSET_BITS=64, _LARGEFILE_SOURCE and _
> > LARGEFILE64_SOURCE). The issue also appears to happen with guile 2.2.
> >
> > The memory leaks start only after the offset exceeds maximum positive
> > value for a 32-bit signed integer. ftell and seek do work as expected
> > (given how lseek should work with large file support).
> >
> > Appended is a program that illustrates the problem. The first seek
> > simply skips the part of the file where you won't see a memory leak.
> > If you comment out ftell and the second seek lines and un-comment the
> > lines that follow them, there is no memory leak.
> >
> > Is this a bug in guile or should we be doing things differently? If
> > this is a known issue, is there a recommended work around?
> >
> > Thanks,
> > Anand
> >
> > (define MAX_SIGNED_INT 2147483647)
> > (define BYTES_TO_READ 10)
> >
> > (define file "/tmp/test.pcap") ;sample file greater than 2.5GB
> >
> > (define (traverse file)
> > (let* ((port (open-input-file file #:binary #t))
> > (file-sz (stat:size (stat port)))
> > (ua (make-bytevector BYTES_TO_READ 0))
> > (cur-offset 0))
> > (seek port (- MAX_UNSIGNED_INT 1000) SEEK_CUR)
> > (while (< (ftell port) (- file-sz BYTES_TO_READ))
> > ;(while (< cur-offset (- file-sz BYTES_TO_READ))
> > (seek port BYTES_TO_READ SEEK_CUR)
> > ;(get-bytevector-n! port ua 0 BYTES_TO_READ)
> > (set! cur-offset (+ BYTES_TO_READ cur-offset)))
> > (close-port port)))
> >
> > (traverse file)
>

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