From 99b5382bffd59c6957b7b8f773a7ed27ad68991a Mon Sep 17 00:00:00 2001 From: Parav Pandit Date: Wed, 25 Nov 2020 11:16:19 +0200 Subject: [PATCH] devlink: Hold rtnl lock while reading netdev attributes [ Upstream commit b187c9b4178b87954dbc94e78a7094715794714f ] A netdevice of a devlink port can be moved to different net namespace than its parent devlink instance. This scenario occurs when devlink reload is not used. When netdevice is undergoing migration to net namespace, its ifindex and name may change. In such use case, devlink port query may read stale netdev attributes. Fix it by reading them under rtnl lock. Fixes: bfcd3a466172 ("Introduce devlink infrastructure") Signed-off-by: Parav Pandit Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/core/devlink.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/core/devlink.c b/net/core/devlink.c index 79f54ae71422..0ac02cab3087 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -562,6 +562,8 @@ static int devlink_nl_port_fill(struct sk_buff *msg, struct devlink *devlink, if (nla_put_u32(msg, DEVLINK_ATTR_PORT_INDEX, devlink_port->index)) goto nla_put_failure; + /* Hold rtnl lock while accessing port's netdev attributes. */ + rtnl_lock(); spin_lock_bh(&devlink_port->type_lock); if (nla_put_u16(msg, DEVLINK_ATTR_PORT_TYPE, devlink_port->type)) goto nla_put_failure_type_locked; @@ -588,6 +590,7 @@ static int devlink_nl_port_fill(struct sk_buff *msg, struct devlink *devlink, goto nla_put_failure_type_locked; } spin_unlock_bh(&devlink_port->type_lock); + rtnl_unlock(); if (devlink_nl_port_attrs_put(msg, devlink_port)) goto nla_put_failure; @@ -596,6 +599,7 @@ static int devlink_nl_port_fill(struct sk_buff *msg, struct devlink *devlink, nla_put_failure_type_locked: spin_unlock_bh(&devlink_port->type_lock); + rtnl_unlock(); nla_put_failure: genlmsg_cancel(msg, hdr); return -EMSGSIZE;