linux/net/core/lock_debug.c
Jakub Kicinski 22cbc1ee26 netdev: fix the locking for netdev notifications
Kuniyuki reports that the assert for netdev lock fires when
there are netdev event listeners (otherwise we skip the netlink
event generation).

Correct the locking when coming from the notifier.

The NETDEV_XDP_FEAT_CHANGE notifier is already fully locked,
it's the documentation that's incorrect.

Fixes: 99e44f39a8 ("netdev: depend on netdev->lock for xdp features")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Reported-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/20250410171019.62128-1-kuniyu@amazon.com
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250416030447.1077551-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-17 18:55:14 -07:00

122 lines
3 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* Copyright Amazon.com Inc. or its affiliates. */
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/notifier.h>
#include <linux/rtnetlink.h>
#include <net/net_namespace.h>
#include <net/netdev_lock.h>
#include <net/netns/generic.h>
int netdev_debug_event(struct notifier_block *nb, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct net *net = dev_net(dev);
enum netdev_cmd cmd = event;
/* Keep enum and don't add default to trigger -Werror=switch */
switch (cmd) {
case NETDEV_XDP_FEAT_CHANGE:
netdev_assert_locked(dev);
fallthrough;
case NETDEV_CHANGE:
case NETDEV_REGISTER:
case NETDEV_UP:
netdev_ops_assert_locked(dev);
fallthrough;
case NETDEV_DOWN:
case NETDEV_REBOOT:
case NETDEV_UNREGISTER:
case NETDEV_CHANGEMTU:
case NETDEV_CHANGEADDR:
case NETDEV_PRE_CHANGEADDR:
case NETDEV_GOING_DOWN:
case NETDEV_FEAT_CHANGE:
case NETDEV_BONDING_FAILOVER:
case NETDEV_PRE_UP:
case NETDEV_PRE_TYPE_CHANGE:
case NETDEV_POST_TYPE_CHANGE:
case NETDEV_POST_INIT:
case NETDEV_PRE_UNINIT:
case NETDEV_RELEASE:
case NETDEV_NOTIFY_PEERS:
case NETDEV_JOIN:
case NETDEV_CHANGEUPPER:
case NETDEV_RESEND_IGMP:
case NETDEV_PRECHANGEMTU:
case NETDEV_CHANGEINFODATA:
case NETDEV_BONDING_INFO:
case NETDEV_PRECHANGEUPPER:
case NETDEV_CHANGELOWERSTATE:
case NETDEV_UDP_TUNNEL_PUSH_INFO:
case NETDEV_UDP_TUNNEL_DROP_INFO:
case NETDEV_CHANGE_TX_QUEUE_LEN:
case NETDEV_CVLAN_FILTER_PUSH_INFO:
case NETDEV_CVLAN_FILTER_DROP_INFO:
case NETDEV_SVLAN_FILTER_PUSH_INFO:
case NETDEV_SVLAN_FILTER_DROP_INFO:
case NETDEV_OFFLOAD_XSTATS_ENABLE:
case NETDEV_OFFLOAD_XSTATS_DISABLE:
case NETDEV_OFFLOAD_XSTATS_REPORT_USED:
case NETDEV_OFFLOAD_XSTATS_REPORT_DELTA:
ASSERT_RTNL();
break;
case NETDEV_CHANGENAME:
ASSERT_RTNL_NET(net);
break;
}
return NOTIFY_DONE;
}
EXPORT_SYMBOL_NS_GPL(netdev_debug_event, "NETDEV_INTERNAL");
static int rtnl_net_debug_net_id;
static int __net_init rtnl_net_debug_net_init(struct net *net)
{
struct notifier_block *nb;
nb = net_generic(net, rtnl_net_debug_net_id);
nb->notifier_call = netdev_debug_event;
return register_netdevice_notifier_net(net, nb);
}
static void __net_exit rtnl_net_debug_net_exit(struct net *net)
{
struct notifier_block *nb;
nb = net_generic(net, rtnl_net_debug_net_id);
unregister_netdevice_notifier_net(net, nb);
}
static struct pernet_operations rtnl_net_debug_net_ops __net_initdata = {
.init = rtnl_net_debug_net_init,
.exit = rtnl_net_debug_net_exit,
.id = &rtnl_net_debug_net_id,
.size = sizeof(struct notifier_block),
};
static struct notifier_block rtnl_net_debug_block = {
.notifier_call = netdev_debug_event,
};
static int __init rtnl_net_debug_init(void)
{
int ret;
ret = register_pernet_subsys(&rtnl_net_debug_net_ops);
if (ret)
return ret;
ret = register_netdevice_notifier(&rtnl_net_debug_block);
if (ret)
unregister_pernet_subsys(&rtnl_net_debug_net_ops);
return ret;
}
subsys_initcall(rtnl_net_debug_init);