Debug SMBD memory leak/usage

[Richard Sharpe]

On Tue, Mar 6, 2018 at 10:40 AM, Timur I. Bakeyev <timur at freebsd.org> wrote:
> On 6 March 2018 at 18:15, Richard Sharpe <realrichardsharpe at gmail.com>
> wrote:
>>
>> On Tue, Mar 6, 2018 at 7:26 AM, Timur I. Bakeyev via samba-technical
>> <samba-technical at lists.samba.org> wrote:
>> > On 6 March 2018 at 07:30, Ralph Böhme <slow at samba.org> wrote:
>> >
>> >> Howdy,
>> >>
>> >> On Tue, Mar 06, 2018 at 04:29:41AM +0100, Timur I. Bakeyev via
>> >> samba-technical wrote:
>> >>
>> >> > I guess I haven't done that for quite a while, as '--enable-dmalloc'
>> >> option
>> >> > from Samba 3.x has disappeared in Samba .4.x and supplying
>> >> -DENABLE_DMALLOC
>> >> > to CFLAGS doesn't add -ldmalloc to the list of libs to link with and
>> >> hence
>> >> > Samba build fails.
>> >>
>> >> never used dmalloc and completely untested, but what about:
>> >>
>> >> ADDITIONAL_CFLAGS="-DENABLE_DMALLOC" \
>> >> ADDITIONAL_LDFLAGS="-ldmalloc" \
>> >> ./configure ...
>> >>
>> >> The ADDITIONAL_* environment variables can be used to pass flags that
>> >> are
>> >> used
>> >> during compilation, but not for configure checks.
>> >>
>> >
>> > Thanks, Ralph! That actually did the trick and I got the the binaries
>> > linked with dmalloc.
>>
>> I remember seeing issues with Samba on FreeBSD and memory consumption.
>>
>> From what I recall, one of the issues seemed to be that TDBs that were
>> volatile would grow continuously all the way up to the 2GB VM that was
>> set aside for them because the free list never seemed to be purged or
>> reused, or something like that.
>
>
> There is at least one recent post
> https://lists.samba.org/archive/samba/2017-December/212577.html
> that seems refers to the same or similar problem... But as usual,
> reproducing the issue is the
> hardest and biggest part of fixing the issue.

You could write a small torture test that just opens and closes lots
of files, or alternatively, run the nbench torture test for several
days. That might show the problem.


-- 
Regards,
Richard Sharpe
(何以解憂？唯有杜康。--曹操)