Re: [patch 08/12] NLM: Fix a circular lock dependency in lockd

[Trond Myklebust <Trond.Myklebust@netapp.com>]

On Tue, 2007-10-09 at 08:13 -0700, Greg KH wrote:
> On Tue, Oct 09, 2007 at 11:00:28AM -0400, Trond Myklebust wrote:
> > 
> > On Mon, 2007-10-08 at 22:01 +0200, Roel Kluin wrote:
> > > Greg KH wrote:
> > > 
> > > @@ -477,10 +479,15 @@ nlmsvc_testlock(struct svc_rqst *rqstp, 
> > >  
> > >  	if (block == NULL) {
> > >  		struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
> > > +		struct nlm_host	*host;
> > >  
> > >  		if (conf == NULL)
> > >  			return nlm_granted;
> > > -		block = nlmsvc_create_block(rqstp, file, lock, cookie);
> > > +		/* Create host handle for callback */
> > > +		host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len);
> > > +		if (host == NULL)
> > > +			return nlm_lck_denied_nolocks;
> > > +		block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
> > >  		if (block == NULL) {
> > >  			kfree(conf);
> > >  			return nlm_granted;
> > > 
> > > To be frankly I don't know what this is about, but shouldn't conf be freed if host == NULL?
> > 
> > Thanks for spotting this!
> > 
> > Greg, should I resend this patch, or would you prefer an incremental
> > fix?
> 
> An incremental one would be best.
> 
> thanks,
> 
> greg k-h

Please see the attachment.

Cheers
  Trond

--- Begin Message ---

• Subject: No Subject
• From: Trond Myklebust <Trond.Myklebust@netapp.com>
• Date: Tue, 9 Oct 2007 10:55:45 -0400
• Lockd: Fix a memory leak in nlmsvc_testlock

The recent fix for a circular lock dependency unfortunately introduced a
potential memory leak in the event where the call to nlmsvc_lookup_host
fails for some reason.

Thanks to Roel Kluin for spotting this.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---

 fs/lockd/svclock.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index d098c7a..d120ec3 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -485,8 +485,10 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
 			return nlm_granted;
 		/* Create host handle for callback */
 		host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len);
-		if (host == NULL)
+		if (host == NULL) {
+			kfree(conf);
 			return nlm_lck_denied_nolocks;
+		}
 		block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
 		if (block == NULL) {
 			kfree(conf);

--- End Message ---