Commit 1a48db3f authored by Anna Schumaker's avatar Anna Schumaker
Browse files

sunrpc: Fix potential race conditions in rpc_sysfs_xprt_state_change() 



We need to use test_and_set_bit() when changing xprt state flags to
avoid potentially getting xps->xps_nactive out of sync.

Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 776d794f

net/sunrpc/sysfs.c

+19 −16
Original line number Diff line number Diff line
@@ -309,18 +309,20 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj, 
		goto release_tasks;

	}

	if (offline) {

		set_bit(XPRT_OFFLINE, &xprt->state);

		if (!test_and_set_bit(XPRT_OFFLINE, &xprt->state)) {

			spin_lock(&xps->xps_lock);

			xps->xps_nactive--;

			spin_unlock(&xps->xps_lock);

		}

	} else if (online) {

		clear_bit(XPRT_OFFLINE, &xprt->state);

		if (test_and_clear_bit(XPRT_OFFLINE, &xprt->state)) {

			spin_lock(&xps->xps_lock);

			xps->xps_nactive++;

			spin_unlock(&xps->xps_lock);

		}

	} else if (remove) {

		if (test_bit(XPRT_OFFLINE, &xprt->state)) {

			set_bit(XPRT_REMOVE, &xprt->state);

			if (!test_and_set_bit(XPRT_REMOVE, &xprt->state)) {

				xprt_force_disconnect(xprt);

				if (test_bit(XPRT_CONNECTED, &xprt->state)) {

					if (!xprt->sending.qlen &&
@@ -329,6 +331,7 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj, 
					    !atomic_long_read(&xprt->queuelen))

						rpc_xprt_switch_remove_xprt(xps, xprt);

				}

			}

		} else {

			count = -EINVAL;

		}