lkml.org 
[lkml]   [2016]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.7 027/184] bonding: Fix bonding crash
Date
4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mahesh Bandewar <maheshb@google.com>


[ Upstream commit 24b27fc4cdf9e10c5e79e5923b6b7c2c5c95096c ]

Following few steps will crash kernel -

(a) Create bonding master
> modprobe bonding miimon=50
(b) Create macvlan bridge on eth2
> ip link add link eth2 dev mvl0 address aa:0:0:0:0:01 \
type macvlan
(c) Now try adding eth2 into the bond
> echo +eth2 > /sys/class/net/bond0/bonding/slaves
<crash>

Bonding does lots of things before checking if the device enslaved is
busy or not.

In this case when the notifier call-chain sends notifications, the
bond_netdev_event() assumes that the rx_handler /rx_handler_data is
registered while the bond_enslave() hasn't progressed far enough to
register rx_handler for the new slave.

This patch adds a rx_handler check that can be performed right at the
beginning of the enslave code to avoid getting into this situation.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/bonding/bond_main.c | 7 ++++---
include/linux/netdevice.h | 1 +
net/core/dev.c | 16 ++++++++++++++++
3 files changed, 21 insertions(+), 3 deletions(-)

--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1341,9 +1341,10 @@ int bond_enslave(struct net_device *bond
slave_dev->name);
}

- /* already enslaved */
- if (slave_dev->flags & IFF_SLAVE) {
- netdev_dbg(bond_dev, "Error: Device was already enslaved\n");
+ /* already in-use? */
+ if (netdev_is_rx_handler_busy(slave_dev)) {
+ netdev_err(bond_dev,
+ "Error: Device is in use and cannot be enslaved\n");
return -EBUSY;
}

--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3225,6 +3225,7 @@ static inline void napi_free_frags(struc
napi->skb = NULL;
}

+bool netdev_is_rx_handler_busy(struct net_device *dev);
int netdev_rx_handler_register(struct net_device *dev,
rx_handler_func_t *rx_handler,
void *rx_handler_data);
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3979,6 +3979,22 @@ sch_handle_ingress(struct sk_buff *skb,
}

/**
+ * netdev_is_rx_handler_busy - check if receive handler is registered
+ * @dev: device to check
+ *
+ * Check if a receive handler is already registered for a given device.
+ * Return true if there one.
+ *
+ * The caller must hold the rtnl_mutex.
+ */
+bool netdev_is_rx_handler_busy(struct net_device *dev)
+{
+ ASSERT_RTNL();
+ return dev && rtnl_dereference(dev->rx_handler);
+}
+EXPORT_SYMBOL_GPL(netdev_is_rx_handler_busy);
+
+/**
* netdev_rx_handler_register - register receive handler
* @dev: device to register a handler for
* @rx_handler: receive handler to register

\
 
 \ /
  Last update: 2016-09-23 00:04    [W:0.538 / U:0.352 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site