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Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet X-Patchwork-Delegate: kuba@kernel.org Using dev_base_lock is not preventing from reading garbage. Use dev_addr_sem instead. Signed-off-by: Eric Dumazet --- include/linux/netdevice.h | 1 + net/core/dev.c | 2 +- net/core/net-sysfs.c | 10 +++++++--- 3 files changed, 9 insertions(+), 4 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index bed8de91e91a4bd83fe80f6835643af68f1adc53..b9140499630fa84108a1f22a2987c0c1934e8f8d 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4031,6 +4031,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa, struct netlink_ext_ack *extack); int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, struct netlink_ext_ack *extack); +extern struct rw_semaphore dev_addr_sem; int dev_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name); int dev_get_port_parent_id(struct net_device *dev, struct netdev_phys_item_id *ppid, bool recurse); diff --git a/net/core/dev.c b/net/core/dev.c index 027d0b7976f337df885266aeab2c90fe631decf1..2b96d1ed7f481cbd022368b3f16608cce4c6bc49 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8922,7 +8922,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa, } EXPORT_SYMBOL(dev_set_mac_address); -static DECLARE_RWSEM(dev_addr_sem); +DECLARE_RWSEM(dev_addr_sem); int dev_set_mac_address_user(struct net_device *dev, struct sockaddr *sa, struct netlink_ext_ack *extack) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 678e4be690821c5cdb933f5e91af2247ebecb830..23ef2df549c3036a702f3be1dca1eda14ee5e76f 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -142,17 +142,21 @@ static ssize_t name_assign_type_show(struct device *dev, } static DEVICE_ATTR_RO(name_assign_type); -/* use same locking rules as GIFHWADDR ioctl's */ +/* use same locking rules as GIFHWADDR ioctl's (dev_get_mac_address()) */ static ssize_t address_show(struct device *dev, struct device_attribute *attr, char *buf) { struct net_device *ndev = to_net_dev(dev); ssize_t ret = -EINVAL; - read_lock(&dev_base_lock); + down_read(&dev_addr_sem); + + rcu_read_lock(); if (dev_isalive(ndev)) ret = sysfs_format_mac(buf, ndev->dev_addr, ndev->addr_len); - read_unlock(&dev_base_lock); + rcu_read_unlock(); + + up_read(&dev_addr_sem); return ret; } static DEVICE_ATTR_RO(address);