SUNRPC: Fix potential memory corruption

We really should not call rpc_wake_up_queued_task_set_status() with
xprt->snd_task as an argument unless we are certain that is actually an
rpc_task.

Fixes: 0445f92c5d53 ("SUNRPC: Fix disconnection races")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index c8c39f22d3b169a7ea3d41f0892fe5562e676377..59cd97da895b78f0fe559d248597bea66e488373 100644 (file)
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -432,6 +432,7 @@ void                        xprt_release_write(struct rpc_xprt *, struct rpc_task *);
 #define XPRT_CONGESTED         (9)
 #define XPRT_CWND_WAIT         (10)
 #define XPRT_WRITE_SPACE       (11)
+#define XPRT_SND_IS_COOKIE     (12)
 
 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 {

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index fb6db09725c76f00b509b14e1c34d4bc791b31e6..bddd354a0076d7164d913f67efc8b499d365744e 100644 (file)
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -775,9 +775,9 @@ void xprt_force_disconnect(struct rpc_xprt *xprt)
        /* Try to schedule an autoclose RPC call */
        if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
                queue_work(xprtiod_workqueue, &xprt->task_cleanup);
-       else if (xprt->snd_task)
+       else if (xprt->snd_task && !test_bit(XPRT_SND_IS_COOKIE, &xprt->state))
                rpc_wake_up_queued_task_set_status(&xprt->pending,
-                               xprt->snd_task, -ENOTCONN);
+                                                  xprt->snd_task, -ENOTCONN);
        spin_unlock(&xprt->transport_lock);
 }
 EXPORT_SYMBOL_GPL(xprt_force_disconnect);
@@ -866,6 +866,7 @@ bool xprt_lock_connect(struct rpc_xprt *xprt,
                goto out;
        if (xprt->snd_task != task)
                goto out;
+       set_bit(XPRT_SND_IS_COOKIE, &xprt->state);
        xprt->snd_task = cookie;
        ret = true;
 out:
@@ -881,6 +882,7 @@ void xprt_unlock_connect(struct rpc_xprt *xprt, void *cookie)
        if (!test_bit(XPRT_LOCKED, &xprt->state))
                goto out;
        xprt->snd_task =NULL;
+       clear_bit(XPRT_SND_IS_COOKIE, &xprt->state);
        xprt->ops->release_xprt(xprt, NULL);
        xprt_schedule_autodisconnect(xprt);
 out: