@@ -156,20 +156,15 @@ static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
}
static int
-rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name)
+rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name,
+ struct super_block *pipefs_sb)
{
- struct net *net = rpc_net_ns(clnt);
- struct super_block *pipefs_sb;
struct dentry *dentry;
clnt->cl_dentry = NULL;
if (dir_name == NULL)
return 0;
- pipefs_sb = rpc_get_sb_net(net);
- if (!pipefs_sb)
- return 0;
dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt, dir_name);
- rpc_put_sb_net(net);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
clnt->cl_dentry = dentry;
@@ -295,6 +290,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
struct rpc_clnt *clnt = NULL;
struct rpc_auth *auth;
int err;
+ struct super_block *pipefs_sb;
/* sanity check the name before trying to print it */
dprintk("RPC: creating %s client for %s (xprt %p)\n",
@@ -355,9 +351,12 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
atomic_set(&clnt->cl_count, 1);
- err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
- if (err < 0)
- goto out_no_path;
+ pipefs_sb = rpc_get_sb_net(rpc_net_ns(clnt));
+ if (pipefs_sb) {
+ err = rpc_setup_pipedir(clnt, program->pipe_dir_name, pipefs_sb);
+ if (err)
+ goto out_no_path;
+ }
auth = rpcauth_create(args->authflavor, clnt);
if (IS_ERR(auth)) {
@@ -370,11 +369,16 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
/* save the nodename */
rpc_clnt_set_nodename(clnt, utsname()->nodename);
rpc_register_client(clnt);
+ if (pipefs_sb)
+ rpc_put_sb_net(rpc_net_ns(clnt));
return clnt;
out_no_auth:
- rpc_clnt_remove_pipedir(clnt);
+ if (pipefs_sb)
+ __rpc_clnt_remove_pipedir(clnt);
out_no_path:
+ if (pipefs_sb)
+ rpc_put_sb_net(rpc_net_ns(clnt));
kfree(clnt->cl_principal);
out_no_principal:
rpc_free_iostats(clnt->cl_metrics);
@@ -1121,6 +1121,7 @@ rpc_fill_super(struct super_block *sb, void *data, int silent)
return -ENOMEM;
dprintk("RPC: sending pipefs MOUNT notification for net %p%s\n",
net, NET_NAME(net));
+ mutex_lock(&sn->pipefs_sb_lock);
sn->pipefs_sb = sb;
err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
RPC_PIPEFS_MOUNT,
@@ -1128,6 +1129,7 @@ rpc_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto err_depopulate;
sb->s_fs_info = get_net(net);
+ mutex_unlock(&sn->pipefs_sb_lock);
return 0;
err_depopulate:
@@ -1136,6 +1138,7 @@ err_depopulate:
sb);
sn->pipefs_sb = NULL;
__rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
+ mutex_unlock(&sn->pipefs_sb_lock);
return err;
}
This is a note to let you know that I have just added a patch titled SUNRPC: fix races on PipeFS MOUNT notifications to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.5. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From c03d3ce1141fe4d42271a401cb8287fad408b215 Mon Sep 17 00:00:00 2001 From: Stanislav Kinsbursky <skinsbursky@parallels.com> Date: Mon, 24 Jun 2013 11:52:38 +0400 Subject: SUNRPC: fix races on PipeFS MOUNT notifications commit 384816051ca9125cd54750e59c780c2a2655fa4f upstream. Below are races, when RPC client can be created without PiepFS dentries CPU#0 CPU#1 ----------------------------- ----------------------------- rpc_new_client rpc_fill_super rpc_setup_pipedir mutex_lock(&sn->pipefs_sb_lock) rpc_get_sb_net == NULL (no per-net PipeFS superblock) sn->pipefs_sb = sb; notifier_call_chain(MOUNT) (client is not in the list) rpc_register_client (client without pipes dentries) To fix this patch: 1) makes PipeFS mount notification call with pipefs_sb_lock being held. 2) releases pipefs_sb_lock on new SUNRPC client creation only after registration. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- net/sunrpc/clnt.c | 26 +++++++++++++++----------- net/sunrpc/rpc_pipe.c | 3 +++ 2 files changed, 18 insertions(+), 11 deletions(-) -- 1.8.1.2