diff mbox series

nfsd: don't ignore the return code of svc_proc_register()

Message ID 20250206-nfsd-fixes-v1-1-c6647b92ca6f@kernel.org (mailing list archive)
State In Next
Delegated to: Chuck Lever
Headers show
Series nfsd: don't ignore the return code of svc_proc_register() | expand

Commit Message

Jeff Layton Feb. 6, 2025, 6:12 p.m. UTC 
Currently, nfsd_proc_stat_init() ignores the return value of
svc_proc_register(). If the procfile creation fails, then the kernel
will WARN when it tries to remove the entry later.

Fix nfsd_proc_stat_init() to return the same type of pointer as
svc_proc_register(), and fix up nfsd_net_init() to check that and fail
the nfsd_net construction if it occurs.

svc_proc_register() can fail if the dentry can't be allocated, or if an
identical dentry already exists. The second case is pretty unlikely in
the nfsd_net construction codepath, so if this happens, return -ENOMEM.

Fixes: 93483ac5fec6 ("nfsd: expose /proc/net/sunrpc/nfsd in net namespaces")
Reported-by: syzbot+e34ad04f27991521104c@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-nfs/67a47501.050a0220.19061f.05f9.GAE@google.com/
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
I looked at the console log from the report, and syzkaller is doing
fault injection on allocations. You can see the stack where the "nfsd"
directory under /proc failed to be created due to one. This is a pretty
unlikely bug under normal circumstances, but it's simple to fix. The
problem predates the patch in Fixes:, but it's not worth the effort to
backport this to anything earlier.
---
 fs/nfsd/nfsctl.c | 9 ++++++++-
 fs/nfsd/stats.c  | 4 ++--
 fs/nfsd/stats.h  | 2 +-
 3 files changed, 11 insertions(+), 4 deletions(-)


---
base-commit: ebbdc9429c39336a406b191cfe84bca2c12c2f73
change-id: 20250206-nfsd-fixes-8e61bdf66347

Best regards,

Comments

Chuck Lever Feb. 6, 2025, 6:17 p.m. UTC | #1 
On 2/6/25 1:12 PM, Jeff Layton wrote:
> Currently, nfsd_proc_stat_init() ignores the return value of
> svc_proc_register(). If the procfile creation fails, then the kernel
> will WARN when it tries to remove the entry later.
> 
> Fix nfsd_proc_stat_init() to return the same type of pointer as
> svc_proc_register(), and fix up nfsd_net_init() to check that and fail
> the nfsd_net construction if it occurs.
> 
> svc_proc_register() can fail if the dentry can't be allocated, or if an
> identical dentry already exists. The second case is pretty unlikely in
> the nfsd_net construction codepath, so if this happens, return -ENOMEM.
> 
> Fixes: 93483ac5fec6 ("nfsd: expose /proc/net/sunrpc/nfsd in net namespaces")
> Reported-by: syzbot+e34ad04f27991521104c@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/linux-nfs/67a47501.050a0220.19061f.05f9.GAE@google.com/
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> I looked at the console log from the report, and syzkaller is doing
> fault injection on allocations. You can see the stack where the "nfsd"
> directory under /proc failed to be created due to one. This is a pretty
> unlikely bug under normal circumstances, but it's simple to fix. The
> problem predates the patch in Fixes:, but it's not worth the effort to
> backport this to anything earlier.

I'd prefer to document this by labeling the actual commit that
introduced the problem in the Fixes: tag, then using

"Cc: stable # vN.M"

to block automatic backporting to LTS kernels where this patch won't
apply cleanly. I can derive the values of N and M from the commit you
mention above, but do you happen to know the actual culprit commit?


> ---
>  fs/nfsd/nfsctl.c | 9 ++++++++-
>  fs/nfsd/stats.c  | 4 ++--
>  fs/nfsd/stats.h  | 2 +-
>  3 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index 95ea4393305bd38493b640fbaba2e8f57f5a501d..583eda0df54dca394de4bbe8d148be2892df39cb 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -2204,8 +2204,14 @@ static __net_init int nfsd_net_init(struct net *net)
>  					  NFSD_STATS_COUNTERS_NUM);
>  	if (retval)
>  		goto out_repcache_error;
> +
>  	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
>  	nn->nfsd_svcstats.program = &nfsd_programs[0];
> +	if (!nfsd_proc_stat_init(net)) {
> +		retval = -ENOMEM;
> +		goto out_proc_error;
> +	}
> +
>  	for (i = 0; i < sizeof(nn->nfsd_versions); i++)
>  		nn->nfsd_versions[i] = nfsd_support_version(i);
>  	for (i = 0; i < sizeof(nn->nfsd4_minorversions); i++)
> @@ -2215,12 +2221,13 @@ static __net_init int nfsd_net_init(struct net *net)
>  	nfsd4_init_leases_net(nn);
>  	get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
>  	seqlock_init(&nn->writeverf_lock);
> -	nfsd_proc_stat_init(net);
>  #if IS_ENABLED(CONFIG_NFS_LOCALIO)
>  	INIT_LIST_HEAD(&nn->local_clients);
>  #endif
>  	return 0;
>  
> +out_proc_error:
> +	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
>  out_repcache_error:
>  	nfsd_idmap_shutdown(net);
>  out_idmap_error:
> diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
> index bb22893f1157e4c159e123b6d8e25b8eab52e187..f7eaf95e20fc8758566f469c6c2de79119fea070 100644
> --- a/fs/nfsd/stats.c
> +++ b/fs/nfsd/stats.c
> @@ -73,11 +73,11 @@ static int nfsd_show(struct seq_file *seq, void *v)
>  
>  DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);
>  
> -void nfsd_proc_stat_init(struct net *net)
> +struct proc_dir_entry *nfsd_proc_stat_init(struct net *net)
>  {
>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
>  
> -	svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
> +	return svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
>  }
>  
>  void nfsd_proc_stat_shutdown(struct net *net)
> diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
> index 04aacb6c36e2576ba231ee481e3a3e9e9f255a61..e4efb0e4e56d467c13eaa5a1dd312c85dadeb4b8 100644
> --- a/fs/nfsd/stats.h
> +++ b/fs/nfsd/stats.h
> @@ -10,7 +10,7 @@
>  #include <uapi/linux/nfsd/stats.h>
>  #include <linux/percpu_counter.h>
>  
> -void nfsd_proc_stat_init(struct net *net);
> +struct proc_dir_entry *nfsd_proc_stat_init(struct net *net);
>  void nfsd_proc_stat_shutdown(struct net *net);
>  
>  static inline void nfsd_stats_rc_hits_inc(struct nfsd_net *nn)
> 
> ---
> base-commit: ebbdc9429c39336a406b191cfe84bca2c12c2f73
> change-id: 20250206-nfsd-fixes-8e61bdf66347
> 
> Best regards,
Jeff Layton Feb. 6, 2025, 6:29 p.m. UTC | #2 
On Thu, 2025-02-06 at 13:17 -0500, Chuck Lever wrote:
> On 2/6/25 1:12 PM, Jeff Layton wrote:
> > Currently, nfsd_proc_stat_init() ignores the return value of
> > svc_proc_register(). If the procfile creation fails, then the kernel
> > will WARN when it tries to remove the entry later.
> > 
> > Fix nfsd_proc_stat_init() to return the same type of pointer as
> > svc_proc_register(), and fix up nfsd_net_init() to check that and fail
> > the nfsd_net construction if it occurs.
> > 
> > svc_proc_register() can fail if the dentry can't be allocated, or if an
> > identical dentry already exists. The second case is pretty unlikely in
> > the nfsd_net construction codepath, so if this happens, return -ENOMEM.
> > 
> > Fixes: 93483ac5fec6 ("nfsd: expose /proc/net/sunrpc/nfsd in net namespaces")
> > Reported-by: syzbot+e34ad04f27991521104c@syzkaller.appspotmail.com
> > Closes: https://lore.kernel.org/linux-nfs/67a47501.050a0220.19061f.05f9.GAE@google.com/
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> > I looked at the console log from the report, and syzkaller is doing
> > fault injection on allocations. You can see the stack where the "nfsd"
> > directory under /proc failed to be created due to one. This is a pretty
> > unlikely bug under normal circumstances, but it's simple to fix. The
> > problem predates the patch in Fixes:, but it's not worth the effort to
> > backport this to anything earlier.
> 
> I'd prefer to document this by labeling the actual commit that
> introduced the problem in the Fixes: tag, then using
> 
> "Cc: stable # vN.M"
> 
> to block automatic backporting to LTS kernels where this patch won't
> apply cleanly. I can derive the values of N and M from the commit you
> mention above, but do you happen to know the actual culprit commit?
> 
> 

Unfortunately this bug goes back to the initial 2.6.12 import into git.
I didn't look earlier. Note that nfsd is not alone here. Ignoring the
result of proc_create_data() is very common.

If you want to drop the Fixes: tag, and add the Cc: stable instead,
then that's fine with me. Whatever works best.


> > ---
> >  fs/nfsd/nfsctl.c | 9 ++++++++-
> >  fs/nfsd/stats.c  | 4 ++--
> >  fs/nfsd/stats.h  | 2 +-
> >  3 files changed, 11 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> > index 95ea4393305bd38493b640fbaba2e8f57f5a501d..583eda0df54dca394de4bbe8d148be2892df39cb 100644
> > --- a/fs/nfsd/nfsctl.c
> > +++ b/fs/nfsd/nfsctl.c
> > @@ -2204,8 +2204,14 @@ static __net_init int nfsd_net_init(struct net *net)
> >  					  NFSD_STATS_COUNTERS_NUM);
> >  	if (retval)
> >  		goto out_repcache_error;
> > +
> >  	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
> >  	nn->nfsd_svcstats.program = &nfsd_programs[0];
> > +	if (!nfsd_proc_stat_init(net)) {
> > +		retval = -ENOMEM;
> > +		goto out_proc_error;
> > +	}
> > +
> >  	for (i = 0; i < sizeof(nn->nfsd_versions); i++)
> >  		nn->nfsd_versions[i] = nfsd_support_version(i);
> >  	for (i = 0; i < sizeof(nn->nfsd4_minorversions); i++)
> > @@ -2215,12 +2221,13 @@ static __net_init int nfsd_net_init(struct net *net)
> >  	nfsd4_init_leases_net(nn);
> >  	get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
> >  	seqlock_init(&nn->writeverf_lock);
> > -	nfsd_proc_stat_init(net);
> >  #if IS_ENABLED(CONFIG_NFS_LOCALIO)
> >  	INIT_LIST_HEAD(&nn->local_clients);
> >  #endif
> >  	return 0;
> >  
> > +out_proc_error:
> > +	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
> >  out_repcache_error:
> >  	nfsd_idmap_shutdown(net);
> >  out_idmap_error:
> > diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
> > index bb22893f1157e4c159e123b6d8e25b8eab52e187..f7eaf95e20fc8758566f469c6c2de79119fea070 100644
> > --- a/fs/nfsd/stats.c
> > +++ b/fs/nfsd/stats.c
> > @@ -73,11 +73,11 @@ static int nfsd_show(struct seq_file *seq, void *v)
> >  
> >  DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);
> >  
> > -void nfsd_proc_stat_init(struct net *net)
> > +struct proc_dir_entry *nfsd_proc_stat_init(struct net *net)
> >  {
> >  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> >  
> > -	svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
> > +	return svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
> >  }
> >  
> >  void nfsd_proc_stat_shutdown(struct net *net)
> > diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
> > index 04aacb6c36e2576ba231ee481e3a3e9e9f255a61..e4efb0e4e56d467c13eaa5a1dd312c85dadeb4b8 100644
> > --- a/fs/nfsd/stats.h
> > +++ b/fs/nfsd/stats.h
> > @@ -10,7 +10,7 @@
> >  #include <uapi/linux/nfsd/stats.h>
> >  #include <linux/percpu_counter.h>
> >  
> > -void nfsd_proc_stat_init(struct net *net);
> > +struct proc_dir_entry *nfsd_proc_stat_init(struct net *net);
> >  void nfsd_proc_stat_shutdown(struct net *net);
> >  
> >  static inline void nfsd_stats_rc_hits_inc(struct nfsd_net *nn)
> > 
> > ---
> > base-commit: ebbdc9429c39336a406b191cfe84bca2c12c2f73
> > change-id: 20250206-nfsd-fixes-8e61bdf66347
> > 
> > Best regards,
> 
>
Chuck Lever Feb. 6, 2025, 6:33 p.m. UTC | #3 
On 2/6/25 1:29 PM, Jeff Layton wrote:
> On Thu, 2025-02-06 at 13:17 -0500, Chuck Lever wrote:
>> On 2/6/25 1:12 PM, Jeff Layton wrote:
>>> Currently, nfsd_proc_stat_init() ignores the return value of
>>> svc_proc_register(). If the procfile creation fails, then the kernel
>>> will WARN when it tries to remove the entry later.
>>>
>>> Fix nfsd_proc_stat_init() to return the same type of pointer as
>>> svc_proc_register(), and fix up nfsd_net_init() to check that and fail
>>> the nfsd_net construction if it occurs.
>>>
>>> svc_proc_register() can fail if the dentry can't be allocated, or if an
>>> identical dentry already exists. The second case is pretty unlikely in
>>> the nfsd_net construction codepath, so if this happens, return -ENOMEM.
>>>
>>> Fixes: 93483ac5fec6 ("nfsd: expose /proc/net/sunrpc/nfsd in net namespaces")
>>> Reported-by: syzbot+e34ad04f27991521104c@syzkaller.appspotmail.com
>>> Closes: https://lore.kernel.org/linux-nfs/67a47501.050a0220.19061f.05f9.GAE@google.com/
>>> Signed-off-by: Jeff Layton <jlayton@kernel.org>
>>> ---
>>> I looked at the console log from the report, and syzkaller is doing
>>> fault injection on allocations. You can see the stack where the "nfsd"
>>> directory under /proc failed to be created due to one. This is a pretty
>>> unlikely bug under normal circumstances, but it's simple to fix. The
>>> problem predates the patch in Fixes:, but it's not worth the effort to
>>> backport this to anything earlier.
>>
>> I'd prefer to document this by labeling the actual commit that
>> introduced the problem in the Fixes: tag, then using
>>
>> "Cc: stable # vN.M"
>>
>> to block automatic backporting to LTS kernels where this patch won't
>> apply cleanly. I can derive the values of N and M from the commit you
>> mention above, but do you happen to know the actual culprit commit?
>>
>>
> 
> Unfortunately this bug goes back to the initial 2.6.12 import into git.
> I didn't look earlier. Note that nfsd is not alone here. Ignoring the
> result of proc_create_data() is very common.
> 
> If you want to drop the Fixes: tag, and add the Cc: stable instead,
> then that's fine with me. Whatever works best.

OK. If we don't know the culprit, then a lone "Cc: stable" should be
sufficient.


>>> ---
>>>  fs/nfsd/nfsctl.c | 9 ++++++++-
>>>  fs/nfsd/stats.c  | 4 ++--
>>>  fs/nfsd/stats.h  | 2 +-
>>>  3 files changed, 11 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
>>> index 95ea4393305bd38493b640fbaba2e8f57f5a501d..583eda0df54dca394de4bbe8d148be2892df39cb 100644
>>> --- a/fs/nfsd/nfsctl.c
>>> +++ b/fs/nfsd/nfsctl.c
>>> @@ -2204,8 +2204,14 @@ static __net_init int nfsd_net_init(struct net *net)
>>>  					  NFSD_STATS_COUNTERS_NUM);
>>>  	if (retval)
>>>  		goto out_repcache_error;
>>> +
>>>  	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
>>>  	nn->nfsd_svcstats.program = &nfsd_programs[0];
>>> +	if (!nfsd_proc_stat_init(net)) {
>>> +		retval = -ENOMEM;
>>> +		goto out_proc_error;
>>> +	}
>>> +
>>>  	for (i = 0; i < sizeof(nn->nfsd_versions); i++)
>>>  		nn->nfsd_versions[i] = nfsd_support_version(i);
>>>  	for (i = 0; i < sizeof(nn->nfsd4_minorversions); i++)
>>> @@ -2215,12 +2221,13 @@ static __net_init int nfsd_net_init(struct net *net)
>>>  	nfsd4_init_leases_net(nn);
>>>  	get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
>>>  	seqlock_init(&nn->writeverf_lock);
>>> -	nfsd_proc_stat_init(net);
>>>  #if IS_ENABLED(CONFIG_NFS_LOCALIO)
>>>  	INIT_LIST_HEAD(&nn->local_clients);
>>>  #endif
>>>  	return 0;
>>>  
>>> +out_proc_error:
>>> +	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
>>>  out_repcache_error:
>>>  	nfsd_idmap_shutdown(net);
>>>  out_idmap_error:
>>> diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
>>> index bb22893f1157e4c159e123b6d8e25b8eab52e187..f7eaf95e20fc8758566f469c6c2de79119fea070 100644
>>> --- a/fs/nfsd/stats.c
>>> +++ b/fs/nfsd/stats.c
>>> @@ -73,11 +73,11 @@ static int nfsd_show(struct seq_file *seq, void *v)
>>>  
>>>  DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);
>>>  
>>> -void nfsd_proc_stat_init(struct net *net)
>>> +struct proc_dir_entry *nfsd_proc_stat_init(struct net *net)
>>>  {
>>>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
>>>  
>>> -	svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
>>> +	return svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
>>>  }
>>>  
>>>  void nfsd_proc_stat_shutdown(struct net *net)
>>> diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
>>> index 04aacb6c36e2576ba231ee481e3a3e9e9f255a61..e4efb0e4e56d467c13eaa5a1dd312c85dadeb4b8 100644
>>> --- a/fs/nfsd/stats.h
>>> +++ b/fs/nfsd/stats.h
>>> @@ -10,7 +10,7 @@
>>>  #include <uapi/linux/nfsd/stats.h>
>>>  #include <linux/percpu_counter.h>
>>>  
>>> -void nfsd_proc_stat_init(struct net *net);
>>> +struct proc_dir_entry *nfsd_proc_stat_init(struct net *net);
>>>  void nfsd_proc_stat_shutdown(struct net *net);
>>>  
>>>  static inline void nfsd_stats_rc_hits_inc(struct nfsd_net *nn)
>>>
>>> ---
>>> base-commit: ebbdc9429c39336a406b191cfe84bca2c12c2f73
>>> change-id: 20250206-nfsd-fixes-8e61bdf66347
>>>
>>> Best regards,
>>
>>
>
Chuck Lever Feb. 6, 2025, 6:41 p.m. UTC | #4 
From: Chuck Lever <chuck.lever@oracle.com>

On Thu, 06 Feb 2025 13:12:13 -0500, Jeff Layton wrote:
> Currently, nfsd_proc_stat_init() ignores the return value of
> svc_proc_register(). If the procfile creation fails, then the kernel
> will WARN when it tries to remove the entry later.
> 
> Fix nfsd_proc_stat_init() to return the same type of pointer as
> svc_proc_register(), and fix up nfsd_net_init() to check that and fail
> the nfsd_net construction if it occurs.
> 
> [...]

Applied to nfsd-testing, thanks!

Added Cc: stable # v6.9

[1/1] nfsd: don't ignore the return code of svc_proc_register()
      commit: 312aef1c1520c10cf035e27c0b0229bea71f0c68

--
Chuck Lever
diff mbox series

Patch

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 95ea4393305bd38493b640fbaba2e8f57f5a501d..583eda0df54dca394de4bbe8d148be2892df39cb 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2204,8 +2204,14 @@  static __net_init int nfsd_net_init(struct net *net)
 					  NFSD_STATS_COUNTERS_NUM);
 	if (retval)
 		goto out_repcache_error;
+
 	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
 	nn->nfsd_svcstats.program = &nfsd_programs[0];
+	if (!nfsd_proc_stat_init(net)) {
+		retval = -ENOMEM;
+		goto out_proc_error;
+	}
+
 	for (i = 0; i < sizeof(nn->nfsd_versions); i++)
 		nn->nfsd_versions[i] = nfsd_support_version(i);
 	for (i = 0; i < sizeof(nn->nfsd4_minorversions); i++)
@@ -2215,12 +2221,13 @@  static __net_init int nfsd_net_init(struct net *net)
 	nfsd4_init_leases_net(nn);
 	get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
 	seqlock_init(&nn->writeverf_lock);
-	nfsd_proc_stat_init(net);
 #if IS_ENABLED(CONFIG_NFS_LOCALIO)
 	INIT_LIST_HEAD(&nn->local_clients);
 #endif
 	return 0;
 
+out_proc_error:
+	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 out_repcache_error:
 	nfsd_idmap_shutdown(net);
 out_idmap_error:
diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
index bb22893f1157e4c159e123b6d8e25b8eab52e187..f7eaf95e20fc8758566f469c6c2de79119fea070 100644
--- a/fs/nfsd/stats.c
+++ b/fs/nfsd/stats.c
@@ -73,11 +73,11 @@  static int nfsd_show(struct seq_file *seq, void *v)
 
 DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);
 
-void nfsd_proc_stat_init(struct net *net)
+struct proc_dir_entry *nfsd_proc_stat_init(struct net *net)
 {
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
-	svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
+	return svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
 }
 
 void nfsd_proc_stat_shutdown(struct net *net)
diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h
index 04aacb6c36e2576ba231ee481e3a3e9e9f255a61..e4efb0e4e56d467c13eaa5a1dd312c85dadeb4b8 100644
--- a/fs/nfsd/stats.h
+++ b/fs/nfsd/stats.h
@@ -10,7 +10,7 @@ 
 #include <uapi/linux/nfsd/stats.h>
 #include <linux/percpu_counter.h>
 
-void nfsd_proc_stat_init(struct net *net);
+struct proc_dir_entry *nfsd_proc_stat_init(struct net *net);
 void nfsd_proc_stat_shutdown(struct net *net);
 
 static inline void nfsd_stats_rc_hits_inc(struct nfsd_net *nn)