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authorAlexey Khoroshilov <khoroshilov@ispras.ru>2014-07-18 03:11:45 +0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2014-08-03 17:14:10 -0400
commit1f70ef96b176bdb3b75230ec68850d83736b387b (patch)
treedd1007c5227311063ef2cfbd0f7ae8d38b345d04
parent411a99adffb4f993eee29759f744de01487044ac (diff)
NFS: add checks for returned value of try_module_get()
There is a couple of places in client code where returned value of try_module_get() is ignored. As a result there is a small chance to premature unload module because of unbalanced refcounting. The patch adds error handling in that places. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
-rw-r--r--fs/nfs/client.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 168aa0d..b7bfa27 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -110,8 +110,8 @@ struct nfs_subversion *get_nfs_version(unsigned int version)
mutex_unlock(&nfs_version_mutex);
}
- if (!IS_ERR(nfs))
- try_module_get(nfs->owner);
+ if (!IS_ERR(nfs) && !try_module_get(nfs->owner))
+ return ERR_PTR(-EAGAIN);
return nfs;
}
@@ -158,7 +158,8 @@ struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
goto error_0;
clp->cl_nfs_mod = cl_init->nfs_mod;
- try_module_get(clp->cl_nfs_mod->owner);
+ if (!try_module_get(clp->cl_nfs_mod->owner))
+ goto error_dealloc;
clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;
@@ -190,6 +191,7 @@ struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
error_cleanup:
put_nfs_version(clp->cl_nfs_mod);
+error_dealloc:
kfree(clp);
error_0:
return ERR_PTR(err);