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SUNRPC: Fix suspicious RCU usage 

We need to hold the rcu_read_lock() when calling rcu_dereference(),
otherwise we can't guarantee that the object being dereferenced still
exists.

Fixes: 39e5d2df ("SUNRPC search xprt switch for sockaddr")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Anna Schumaker 2016-10-26 10:33:31 -04:00
parent 68a564006a
commit bb29dd8433
1 changed files with 5 additions and 2 deletions
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7
net/sunrpc/clnt.c
View File

@ -2753,14 +2753,18 @@ EXPORT_SYMBOL_GPL(rpc_cap_max_reconnect_timeout);
void rpc_clnt_xprt_switch_put(struct rpc_clnt *clnt)
{
rcu_read_lock();
xprt_switch_put(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_put);
void rpc_clnt_xprt_switch_add_xprt(struct rpc_clnt *clnt, struct rpc_xprt *xprt)
{
rcu_read_lock();
rpc_xprt_switch_add_xprt(rcu_dereference(clnt->cl_xpi.xpi_xpswitch),
xprt);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_add_xprt);
@ -2770,9 +2774,8 @@ bool rpc_clnt_xprt_switch_has_addr(struct rpc_clnt *clnt,
struct rpc_xprt_switch *xps;
bool ret;
xps = rcu_dereference(clnt->cl_xpi.xpi_xpswitch);
rcu_read_lock();
xps = rcu_dereference(clnt->cl_xpi.xpi_xpswitch);
ret = rpc_xprt_switch_has_addr(xps, sap);
rcu_read_unlock();
return ret;