[PATCH] Patch for memory leak in vfs_defaults.c

[Christof Schmitt]

On Mon, Apr 09, 2018 at 08:42:50AM -0700, Jeremy Allison via samba-technical wrote:
> On Fri, Apr 06, 2018 at 04:03:08PM -0700, Jeremy Allison wrote:
> > On Fri, Apr 06, 2018 at 04:40:44PM -0400, Andrew Walker via samba-technical wrote:
> > > Hi all,
> > > I encountered an issue where several FreeNAS users on samba 4.7 were
> > > experiencing memory leak resulting in single smbd process consuming all
> > > available RAM and swap space. Disabling the getwd cache significantly
> > > increased rate of leak, and enabling widelinks / disabling unix extensions
> > > made the leak apparently stop. Investigation indicated that the leak was in
> > > vfswrap_getwd().
> > > 
> > > The attached patch resolved the issue.
> > 
> > OK, here is the version I'd like to push. Confirmed fixed by
> > the submitter.
> > 
> > Ralph, can you do a quick review ?
> 
> Ping ! Anyone on the Team, can I get a +1 here please ?
> 
> It's a really bad memory leak on potentially (depending
> on directory cache settings) a hot code path, and I'd
> really like to get it fixed in master and 4.8.next, 4.7.next
> (the only releases it's a problem).
> 
> Plus as the original bug was my fault, it's making me feel
> really bad :-).
> 
> Thanks !
> 
> Jeremy.


Reviewed-by: Christof Schmitt <cs at samba.org>

Christof

> 
> 
> 
> > From 92e8095023f82238c0490fc36a38af0ba9eeed8c Mon Sep 17 00:00:00 2001
> > From: Jeremy Allison <jra at samba.org>
> > Date: Fri, 6 Apr 2018 13:52:52 -0700
> > Subject: [PATCH] s3: smbd: Fix memory leak in vfswrap_getwd()
> > 
> > BUG: https://bugzilla.samba.org/show_bug.cgi?id=13372
> > 
> > Signed-off-by: Andrew Walker <awalker at ixsystems.com>.
> > Reviewed-by: Jeremy Allison <jra at samba.org>
> > ---
> >  source3/modules/vfs_default.c | 9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> > 
> > diff --git a/source3/modules/vfs_default.c b/source3/modules/vfs_default.c
> > index a26bec457ae..a9c87e444fe 100644
> > --- a/source3/modules/vfs_default.c
> > +++ b/source3/modules/vfs_default.c
> > @@ -2229,9 +2229,12 @@ static struct smb_filename *vfswrap_getwd(vfs_handle_struct *handle,
> >  				NULL,
> >  				NULL,
> >  				0);
> > -	if (smb_fname == NULL) {
> > -		SAFE_FREE(result);
> > -	}
> > +	/*
> > +	 * sys_getwd() *always* returns malloced memory.
> > +	 * We must free here to avoid leaks:
> > +	 * BUG:https://bugzilla.samba.org/show_bug.cgi?id=13372
> > +	 */
> > +	SAFE_FREE(result);
> >  	return smb_fname;
> >  }
> >  
> > -- 
> > 2.17.0.484.g0c8726318c-goog
> > 
> 
>