linux/net/core/lock_debug.c
Stanislav Fomichev 04efcee6ef net: hold instance lock during NETDEV_CHANGE
Cosmin reports an issue with ipv6_add_dev being called from
NETDEV_CHANGE notifier:

[ 3455.008776]  ? ipv6_add_dev+0x370/0x620
[ 3455.010097]  ipv6_find_idev+0x96/0xe0
[ 3455.010725]  addrconf_add_dev+0x1e/0xa0
[ 3455.011382]  addrconf_init_auto_addrs+0xb0/0x720
[ 3455.013537]  addrconf_notify+0x35f/0x8d0
[ 3455.014214]  notifier_call_chain+0x38/0xf0
[ 3455.014903]  netdev_state_change+0x65/0x90
[ 3455.015586]  linkwatch_do_dev+0x5a/0x70
[ 3455.016238]  rtnl_getlink+0x241/0x3e0
[ 3455.019046]  rtnetlink_rcv_msg+0x177/0x5e0

Similarly, linkwatch might get to ipv6_add_dev without ops lock:
[ 3456.656261]  ? ipv6_add_dev+0x370/0x620
[ 3456.660039]  ipv6_find_idev+0x96/0xe0
[ 3456.660445]  addrconf_add_dev+0x1e/0xa0
[ 3456.660861]  addrconf_init_auto_addrs+0xb0/0x720
[ 3456.661803]  addrconf_notify+0x35f/0x8d0
[ 3456.662236]  notifier_call_chain+0x38/0xf0
[ 3456.662676]  netdev_state_change+0x65/0x90
[ 3456.663112]  linkwatch_do_dev+0x5a/0x70
[ 3456.663529]  __linkwatch_run_queue+0xeb/0x200
[ 3456.663990]  linkwatch_event+0x21/0x30
[ 3456.664399]  process_one_work+0x211/0x610
[ 3456.664828]  worker_thread+0x1cc/0x380
[ 3456.665691]  kthread+0xf4/0x210

Reclassify NETDEV_CHANGE as a notifier that consistently runs under the
instance lock.

Link: https://lore.kernel.org/netdev/aac073de8beec3e531c86c101b274d434741c28e.camel@nvidia.com/
Reported-by: Cosmin Ratiu <cratiu@nvidia.com>
Tested-by: Cosmin Ratiu <cratiu@nvidia.com>
Fixes: ad7c7b2172 ("net: hold netdev instance lock during sysfs operations")
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250404161122.3907628-1-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-07 11:13:39 -07:00

120 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_REGISTER:
case NETDEV_UP:
case NETDEV_CHANGE:
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:
case NETDEV_XDP_FEAT_CHANGE:
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);