[PATCH AUTOSEL 5.0 004/317] NFS: make nfs_match_client killable

Sasha Levin
2019-05-22T19:59:23Z

From: Roberto Bergantinos Corpas <rbergant@redhat.com>

[ Upstream commit 950a578c6128c2886e295b9c7ecb0b6b22fcc92b ]

Actually we don't do anything with return value from
nfs_wait_client_init_complete in nfs_match_client, as a
consequence if we get a fatal signal and client is not
fully initialised, we'll loop to "again" label

This has been proven to cause soft lockups on some scenarios
(no-carrier but configured network interfaces)

Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfs/client.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 90d71fda65cec..350cfa561e0e8 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -284,6 +284,7 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
struct nfs_client *clp;
const struct sockaddr *sap = data->addr;
struct nfs_net *nn = net_generic(data->net, nfs_net_id);
+ int error;

again:
list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
@@ -296,8 +297,10 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
if (clp->cl_cons_state > NFS_CS_READY) {
refcount_inc(&clp->cl_count);
spin_unlock(&nn->nfs_client_lock);
- nfs_wait_client_init_complete(clp);
+ error = nfs_wait_client_init_complete(clp);
nfs_put_client(clp);
+ if (error < 0)
+ return ERR_PTR(error);
spin_lock(&nn->nfs_client_lock);
goto again;
}
@@ -407,6 +410,8 @@ struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
clp = nfs_match_client(cl_init);
if (clp) {
spin_unlock(&nn->nfs_client_lock);
+ if (IS_ERR(clp))
+ return clp;
if (new)
new->rpc_ops->free_client(new);
return nfs_found_client(cl_init, clp);
--
2.20.1