Client have to be initialized prior to adding it to per-net clients list,
because otherwise there are races, shown below:
CPU#0 CPU#1
_____ _____
nfs_get_client
nfs_alloc_client
list_add(..., nfs_client_list)
rpc_fill_super
rpc_pipefs_event
nfs_get_client_for_event
__rpc_pipefs_event
(clp->cl_rpcclient is uninitialized)
BUG()
init_client
clp->cl_rpcclient = ...
Signed-off-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
---
fs/nfs/client.c | 22 ++++++++++++----------
1 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index ae29d4f..9bf4702 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -525,7 +525,7 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
cl_init->hostname ?: "", cl_init->rpc_ops->version);
/* see if the client already exists */
- do {
+ while (1) {
spin_lock(&nn->nfs_client_lock);
clp = nfs_match_client(cl_init);
@@ -537,10 +537,18 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
spin_unlock(&nn->nfs_client_lock);
new = nfs_alloc_client(cl_init);
- } while (!IS_ERR(new));
+ if (IS_ERR(new)) {
+ dprintk("--> nfs_get_client() = %ld [failed]\n", PTR_ERR(new));
+ return new;
+ }
- dprintk("--> nfs_get_client() = %ld [failed]\n", PTR_ERR(new));
- return new;
+ error = cl_init->rpc_ops->init_client(new, timeparms, ip_addr,
+ authflavour, noresvport);
+ if (error < 0) {
+ nfs_put_client(new);
+ return ERR_PTR(error);
+ }
+ }
/* install a new client and return with it unready */
install_client:
@@ -548,12 +556,6 @@ install_client:
list_add(&clp->cl_share_link, &nn->nfs_client_list);
spin_unlock(&nn->nfs_client_lock);
- error = cl_init->rpc_ops->init_client(clp, timeparms, ip_addr,
- authflavour, noresvport);
- if (error < 0) {
- nfs_put_client(clp);
- return ERR_PTR(error);
- }
dprintk("--> nfs_get_client() = %p [new]\n", clp);
return clp;
--
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