refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations.
Signed-off-by: Elena Reshetova <[email protected]> Signed-off-by: Hans Liljestrand <[email protected]> Signed-off-by: Kees Cook <[email protected]> Signed-off-by: David Windsor <[email protected]> --- fs/nfsd/nfs4state.c | 6 +++--- fs/nfsd/state.h | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index ea1ce57..253fc93 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -568,7 +568,7 @@ alloc_clnt_odstate(struct nfs4_client *clp) co = kmem_cache_zalloc(odstate_slab, GFP_KERNEL); if (co) { co->co_client = clp; - atomic_set(&co->co_odcount, 1); + refcount_set(&co->co_odcount, 1); } return co; } @@ -586,7 +586,7 @@ static inline void get_clnt_odstate(struct nfs4_clnt_odstate *co) { if (co) - atomic_inc(&co->co_odcount); + refcount_inc(&co->co_odcount); } static void @@ -598,7 +598,7 @@ put_clnt_odstate(struct nfs4_clnt_odstate *co) return; fp = co->co_file; - if (atomic_dec_and_lock(&co->co_odcount, &fp->fi_lock)) { + if (refcount_dec_and_lock(&co->co_odcount, &fp->fi_lock)) { list_del(&co->co_perfile); spin_unlock(&fp->fi_lock); diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index f927aa4..58eb5f4 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -466,7 +466,7 @@ struct nfs4_clnt_odstate { struct nfs4_client *co_client; struct nfs4_file *co_file; struct list_head co_perfile; - atomic_t co_odcount; + refcount_t co_odcount; }; /* -- 2.7.4
