NFSD: Fix a null reference case in find_or_create_lock_stateid()

nfsd assigns the nfs4_free_lock_stateid to .sc_free in init_lock_stateid().

If nfsd doesn't go through init_lock_stateid() and put stateid at end,
there is a NULL reference to .sc_free when calling nfs4_put_stid(ns).

This patch let the nfs4_stid.sc_free assignment to nfs4_alloc_stid().

Cc: stable@vger.kernel.org
Fixes: 356a95ece7aa "nfsd: clean up races in lock stateid searching..."
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index 596205d939a1f43f1faa292d31680377045a8589..1fc07a9c70e9c6028342e8c97d183dfe914a343b 100644 (file)
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -223,10 +223,11 @@ nfsd4_alloc_layout_stateid(struct nfsd4_compound_state *cstate,
        struct nfs4_layout_stateid *ls;
        struct nfs4_stid *stp;
 
-       stp = nfs4_alloc_stid(cstate->clp, nfs4_layout_stateid_cache);
+       stp = nfs4_alloc_stid(cstate->clp, nfs4_layout_stateid_cache,
+                                       nfsd4_free_layout_stateid);
        if (!stp)
                return NULL;
-       stp->sc_free = nfsd4_free_layout_stateid;
+
        get_nfs4_file(fp);
        stp->sc_file = fp;
 

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 4b4beaaa4eaac01233f874c7dfdb8d1a6d7cd3d6..a0dee8ae9f97f16a18e40ba19f8e84a45ad1a02b 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -633,8 +633,8 @@ out:
        return co;
 }
 
-struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl,
-                                        struct kmem_cache *slab)
+struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct kmem_cache *slab,
+                                 void (*sc_free)(struct nfs4_stid *))
 {
        struct nfs4_stid *stid;
        int new_id;
@@ -650,6 +650,8 @@ struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl,
        idr_preload_end();
        if (new_id < 0)
                goto out_free;
+
+       stid->sc_free = sc_free;
        stid->sc_client = cl;
        stid->sc_stateid.si_opaque.so_id = new_id;
        stid->sc_stateid.si_opaque.so_clid = cl->cl_clientid;
@@ -675,15 +677,12 @@ out_free:
 static struct nfs4_ol_stateid * nfs4_alloc_open_stateid(struct nfs4_client *clp)
 {
        struct nfs4_stid *stid;
-       struct nfs4_ol_stateid *stp;
 
-       stid = nfs4_alloc_stid(clp, stateid_slab);
+       stid = nfs4_alloc_stid(clp, stateid_slab, nfs4_free_ol_stateid);
        if (!stid)
                return NULL;
 
-       stp = openlockstateid(stid);
-       stp->st_stid.sc_free = nfs4_free_ol_stateid;
-       return stp;
+       return openlockstateid(stid);
 }
 
 static void nfs4_free_deleg(struct nfs4_stid *stid)
@@ -781,11 +780,10 @@ alloc_init_deleg(struct nfs4_client *clp, struct svc_fh *current_fh,
                goto out_dec;
        if (delegation_blocked(&current_fh->fh_handle))
                goto out_dec;
-       dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab));
+       dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab, nfs4_free_deleg));
        if (dp == NULL)
                goto out_dec;
 
-       dp->dl_stid.sc_free = nfs4_free_deleg;
        /*
         * delegation seqid's are never incremented.  The 4.1 special
         * meaning of seqid 0 isn't meaningful, really, but let's avoid
@@ -5580,7 +5578,6 @@ init_lock_stateid(struct nfs4_ol_stateid *stp, struct nfs4_lockowner *lo,
        stp->st_stateowner = nfs4_get_stateowner(&lo->lo_owner);
        get_nfs4_file(fp);
        stp->st_stid.sc_file = fp;
-       stp->st_stid.sc_free = nfs4_free_lock_stateid;
        stp->st_access_bmap = 0;
        stp->st_deny_bmap = open_stp->st_deny_bmap;
        stp->st_openstp = open_stp;
@@ -5623,7 +5620,7 @@ find_or_create_lock_stateid(struct nfs4_lockowner *lo, struct nfs4_file *fi,
        lst = find_lock_stateid(lo, fi);
        if (lst == NULL) {
                spin_unlock(&clp->cl_lock);
-               ns = nfs4_alloc_stid(clp, stateid_slab);
+               ns = nfs4_alloc_stid(clp, stateid_slab, nfs4_free_lock_stateid);
                if (ns == NULL)
                        return NULL;
 

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index c9399366f9dfc73b343d079fbad2dc2127927aae..4516e8b7d776305d94fb89f86256ee3fc54dec27 100644 (file)
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -603,8 +603,8 @@ extern __be32 nfs4_preprocess_stateid_op(struct svc_rqst *rqstp,
 __be32 nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
                     stateid_t *stateid, unsigned char typemask,
                     struct nfs4_stid **s, struct nfsd_net *nn);
-struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl,
-               struct kmem_cache *slab);
+struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct kmem_cache *slab,
+                                 void (*sc_free)(struct nfs4_stid *));
 void nfs4_unhash_stid(struct nfs4_stid *s);
 void nfs4_put_stid(struct nfs4_stid *s);
 void nfs4_inc_and_copy_stateid(stateid_t *dst, struct nfs4_stid *stid);