[Samba] possible memory leak in ldb module while dbcheck on RODC

Andrej Gessel Andrej.Gessel at janztec.com
Fri Mar 31 07:10:59 UTC 2017


Hello, 

i just checkout git repository and run 
# ./configure.develorer
# make
# make install

As i can read from lib/ldb/wscript it is version 1.1.27?

How can i change to the version 1.1.29?

Regards,

Andrej


-----Ursprüngliche Nachricht-----
Von: samba [mailto:samba-bounces at lists.samba.org] Im Auftrag von L.P.H. van Belle via samba
Gesendet: Freitag, 31. März 2017 09:03
An: samba at lists.samba.org
Betreff: Re: [Samba] possible memory leak in ldb module while dbcheck on RODC

What is the ldb version your using? 
You need : 1.1.29 with samba 4.5.7. 

Greetz, 

Louis


> -----Oorspronkelijk bericht-----
> Van: samba [mailto:samba-bounces at lists.samba.org] Namens Andrej Gessel 
> via samba
> Verzonden: vrijdag 31 maart 2017 8:55
> Aan: samba at lists.samba.org
> Onderwerp: Re: [Samba] possible memory leak in ldb module while 
> dbcheck on RODC
> 
> Hello,
> 
> my message was not send with my attachment, because content-type was 
> not allowed,  sorry for that.
> 
> i am trying to use Samba 4.5.7 as an RODC and maybe found a memory 
> leak in ldb module.
> 
> There is an known BUG https://bugzilla.samba.org/show_bug.cgi?id=11178 
> and a known fix in dbcheck.
> 
> If i run "samba-tool dbcheck --cross-ncs --fix", this running process 
> starts with ~300MB and use at the end about 1,6GB of memory on test 
> domain with 15000 users and 15000 groups(ntds.dit is only ~150MB). I 
> tried to find out why it is increasing continuously.
> 
> 
> 1) I used memory_profiler and modified dbchecker.py:
> 
> root at buildhost samba # git diff dbchecker.py diff --git a/dbchecker.py 
> b/dbchecker.py index 032c0e7..6fe0d4d 100644
> --- a/dbchecker.py
> +++ b/dbchecker.py
> @@ -17,6 +17,7 @@
> # along with this program.  If not, see <http://www.gnu.org/licenses/>.
> #
> 
> +from memory_profiler import profile
> import ldb
> import samba
> import time
> @@ -356,6 +357,7 @@ systemFlags: -1946157056%s""" % (dn, guid_suffix),
>              return False
>          return True
> 
> +    @profile
>      def do_modify(self, m, controls, msg, validate=True):
>          '''perform a modify with optional verbose output'''
>          if self.verbose:
> @@ -751,6 +753,7 @@ newSuperior: %s""" % (str(from_dn), str(to_rdn),
> str(to_base)))
>                            "Failed to rename object %s into %s" % 
> (obj.dn,
> new_dn)):
>              self.report("Renamed %s into %s" % (obj.dn, new_dn))
> 
> +    @profile
>      def err_wrong_instancetype(self, obj, calculated_instancetype):
>          '''handle a wrong instanceType'''
>          self.report("ERROR: wrong instanceType %s on %s, should be 
> %d" % (obj["instanceType"], obj.dn, calculated_instancetype)) @@ 
> -1541,6 +1544,7 @@ newSuperior: %s""" % (str(from_dn), str(to_rdn),
> str(to_base)))
> 
>          raise KeyError
> 
> +    @profile(precision=4)
>      def check_object(self, dn, attrs=['*']):
>          '''check one object'''
>          if self.verbose:
> 
> Output of memory_profiler shows me additional ~2MB of memory usage 
> after every run of check_object function (show memory_profiler.txt for 
> details partial, because of mailing list limits).
> 
> 2) After i comment out the line in dbchecker.py, memory is not 
> increasing anymore.
> 
> @@ -356,13 +357,14 @@ systemFlags: -1946157056%s""" % (dn, guid_suffix),
>              return False
>          return True
> 
> +    @profile
>      def do_modify(self, m, controls, msg, validate=True):
>          '''perform a modify with optional verbose output'''
>          if self.verbose:
>              self.report(self.samdb.write_ldif(m, ldb.CHANGETYPE_MODIFY))
>          try:
>              controls = controls + ["local_oid:%s:0" % 
> dsdb.DSDB_CONTROL_DBCHECK]
> -            self.samdb.modify(m, controls=controls, validate=validate)
> +#            self.samdb.modify(m, controls=controls, validate=validate)
>          except Exception, err:
>             if self.in_transaction:
>                  raise CommandError("%s : %s" % (msg, err))
> 
> 
> 
> 3) My first idea was that it is python problem with starting c 
> modules, but then i found pyldb.c and py_ldb_modify function in it. 
> Commenting out the line with ldb_request memory stays on the same 
> value and does not increase anymore.
> 
> root at buildhost samba (git)-[samba-4.5.7] # git diff lib/ldb/pyldb.c 
> diff --git a/lib/ldb/pyldb.c b/lib/ldb/pyldb.c index bea837f..ed5309a 
> 100644
> --- a/lib/ldb/pyldb.c
> +++ b/lib/ldb/pyldb.c
> @@ -1255,7 +1255,7 @@ static PyObject *py_ldb_modify(PyLdbObject 
> *self, PyObject *args, PyObject *kwar
>                 return NULL;
>         }
> 
> -       ret = ldb_request(ldb_ctx, req);
> +       //ret = ldb_request(ldb_ctx, req);
>         if (ret == LDB_SUCCESS) {
>                 ret = ldb_wait(req->handle, LDB_WAIT_ALL);
>         }
> 
> 
> 
> So now to my question:
> Is it really a bug or does ldb library do something, that i did not 
> see/understand till now?
> 
> 
> regards,
> 
> Andrej
> 
> Von: samba [mailto:samba-bounces at lists.samba.org] Im Auftrag von 
> Andrej Gessel via samba
> Gesendet: Donnerstag, 30. März 2017 23:33
> An: samba at lists.samba.org
> Betreff: [Samba] possible memory leak in ldb module while dbcheck on 
> RODC
> 
> 
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