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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Reinhard Speyerer <rspmn@arcor.de>,
	Daniele Palmas <dnlplm@gmail.com>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org, linux-usb@vger.kernel.org
Subject: [PATCH AUTOSEL 4.14 26/35] qmi_wwan: avoid RCU stalls on device disconnect when in QMAP mode
Date: Wed, 26 Jun 2019 20:39:14 -0400
Message-ID: <20190627003925.21330-26-sashal@kernel.org> (raw)
In-Reply-To: <20190627003925.21330-1-sashal@kernel.org>

From: Reinhard Speyerer <rspmn@arcor.de>

[ Upstream commit a8fdde1cb830e560208af42b6c10750137f53eb3 ]

Switch qmimux_unregister_device() and qmi_wwan_disconnect() to
use unregister_netdevice_queue() and unregister_netdevice_many()
instead of unregister_netdevice(). This avoids RCU stalls which
have been observed on device disconnect in certain setups otherwise.

Fixes: c6adf77953bc ("net: usb: qmi_wwan: add qmap mux protocol support")
Cc: Daniele Palmas <dnlplm@gmail.com>
Signed-off-by: Reinhard Speyerer <rspmn@arcor.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/qmi_wwan.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 023bb2daa72f..a77223887022 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -247,13 +247,14 @@ static int qmimux_register_device(struct net_device *real_dev, u8 mux_id)
 	return err;
 }
 
-static void qmimux_unregister_device(struct net_device *dev)
+static void qmimux_unregister_device(struct net_device *dev,
+				     struct list_head *head)
 {
 	struct qmimux_priv *priv = netdev_priv(dev);
 	struct net_device *real_dev = priv->real_dev;
 
 	netdev_upper_dev_unlink(real_dev, dev);
-	unregister_netdevice(dev);
+	unregister_netdevice_queue(dev, head);
 
 	/* Get rid of the reference to real_dev */
 	dev_put(real_dev);
@@ -424,7 +425,7 @@ static ssize_t del_mux_store(struct device *d,  struct device_attribute *attr, c
 		ret = -EINVAL;
 		goto err;
 	}
-	qmimux_unregister_device(del_dev);
+	qmimux_unregister_device(del_dev, NULL);
 
 	if (!qmimux_has_slaves(dev))
 		info->flags &= ~QMI_WWAN_FLAG_MUX;
@@ -1423,6 +1424,7 @@ static void qmi_wwan_disconnect(struct usb_interface *intf)
 	struct qmi_wwan_state *info;
 	struct list_head *iter;
 	struct net_device *ldev;
+	LIST_HEAD(list);
 
 	/* called twice if separate control and data intf */
 	if (!dev)
@@ -1435,8 +1437,9 @@ static void qmi_wwan_disconnect(struct usb_interface *intf)
 		}
 		rcu_read_lock();
 		netdev_for_each_upper_dev_rcu(dev->net, ldev, iter)
-			qmimux_unregister_device(ldev);
+			qmimux_unregister_device(ldev, &list);
 		rcu_read_unlock();
+		unregister_netdevice_many(&list);
 		rtnl_unlock();
 		info->flags &= ~QMI_WWAN_FLAG_MUX;
 	}
-- 
2.20.1


  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190627003925.21330-1-sashal@kernel.org>
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 02/35] samples, bpf: fix to change the buffer size for read() Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 03/35] bpf: sockmap, fix use after free from sleep in psock backlog workqueue Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 05/35] mac80211: mesh: fix RCU warning Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 06/35] mac80211: free peer keys before vif down in mesh Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 07/35] mwifiex: Fix possible buffer overflows at parsing bss descriptor Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 08/35] mwifiex: Abort at too short BSS descriptor element Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 09/35] iwlwifi: Fix double-free problems in iwl_req_fw_callback() Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 10/35] bpf: udp: Avoid calling reuseport's bpf_prog from udp_gro Sasha Levin
2019-06-27  0:38 ` [PATCH AUTOSEL 4.14 11/35] netfilter: ipv6: nf_defrag: fix leakage of unqueued fragments Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 12/35] netfilter: ipv6: nf_defrag: accept duplicate fragments again Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 13/35] dt-bindings: can: mcp251x: add mcp25625 support Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 14/35] can: mcp251x: add support for mcp25625 Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 15/35] can: m_can: implement errata "Needless activation of MRAF irq" Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 16/35] can: af_can: Fix error path of can_init() Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 17/35] ibmvnic: Refresh device multicast list after reset Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 21/35] mlxsw: spectrum: Disallow prio-tagged packets when PVID is removed Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 24/35] mac80211: only warn once on chanctx_conf being NULL Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 25/35] qmi_wwan: add support for QMAP padding in the RX path Sasha Levin
2019-06-27  0:39 ` Sasha Levin [this message]
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 27/35] qmi_wwan: extend permitted QMAP mux_id value range Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 29/35] bnx2x: Check if transceiver implements DDM before access Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 31/35] ip6_tunnel: allow not to count pkts on tstats by passing dev as NULL Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 32/35] net: lio_core: fix potential sign-extension overflow on large shift Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 34/35] net: dsa: mv88e6xxx: fix shift of FID bits in mv88e6185_g1_vtu_loadpurge() Sasha Levin
2019-06-27  0:39 ` [PATCH AUTOSEL 4.14 35/35] net :sunrpc :clnt :Fix xps refcount imbalance on the error path Sasha Levin

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