When an interface is being deleted, "/proc/net/dev_snmp6/<interface name>"
is deleted.
The function for this is addrconf_ifdown() in the addrconf_notify() and
it is called by notification, which is NETDEV_UNREGISTER.
But, if NETDEV_CHANGEMTU is triggered after NETDEV_UNREGISTER,
this proc file will be created again.
This recreated proc file will be deleted by netdev_wati_allrefs().
Before netdev_wait_allrefs() is called, creating a new HSR interface
routine can be executed and It tries to create a proc file but it will
find an un-deleted proc file.
At this point, it warns about it.
To avoid this situation, it can use ->dellink() instead of
->ndo_uninit() to release resources because ->dellink() is called
before NETDEV_UNREGISTER.
So, a proc file will not be recreated.
Test commands
ip link add dummy0 type dummy
ip link add dummy1 type dummy
ip link set dummy0 mtu 1300
#SHELL1
while :
do
ip link add hsr0 type hsr slave1 dummy0 slave2 dummy1
done
#SHELL2
while :
do
ip link del hsr0
done
Splat looks like:
[ 9888.980852][ T2752] proc_dir_entry 'dev_snmp6/hsr0' already registered
[ 9888.981797][ C2] WARNING: CPU: 2 PID: 2752 at fs/proc/generic.c:372 proc_register+0x2d5/0x430
[ 9888.981798][ C2] Modules linked in: hsr dummy veth openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6x
[ 9888.981814][ C2] CPU: 2 PID: 2752 Comm: ip Tainted: G W 5.8.0-rc1+ #616
[ 9888.981815][ C2] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 9888.981816][ C2] RIP: 0010:proc_register+0x2d5/0x430
[ 9888.981818][ C2] Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 65 01 00 00 49 8b b5 e0 00 00 00 48 89 ea 40
[ 9888.981819][ C2] RSP: 0018:
ffff8880628dedf0 EFLAGS:
00010286
[ 9888.981821][ C2] RAX:
dffffc0000000008 RBX:
ffff888028c69170 RCX:
ffffffffaae09a62
[ 9888.981822][ C2] RDX:
0000000000000001 RSI:
0000000000000008 RDI:
ffff88806c9f75ac
[ 9888.981823][ C2] RBP:
ffff888028c693f4 R08:
ffffed100d9401bd R09:
ffffed100d9401bd
[ 9888.981824][ C2] R10:
ffffffffaddf406f R11:
0000000000000001 R12:
ffff888028c69308
[ 9888.981825][ C2] R13:
ffff8880663584c8 R14:
dffffc0000000000 R15:
ffffed100518d27e
[ 9888.981827][ C2] FS:
00007f3876b3b0c0(0000) GS:
ffff88806c800000(0000) knlGS:
0000000000000000
[ 9888.981828][ C2] CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
[ 9888.981829][ C2] CR2:
00007f387601a8c0 CR3:
000000004101a002 CR4:
00000000000606e0
[ 9888.981830][ C2] DR0:
0000000000000000 DR1:
0000000000000000 DR2:
0000000000000000
[ 9888.981831][ C2] DR3:
0000000000000000 DR6:
00000000fffe0ff0 DR7:
0000000000000400
[ 9888.981832][ C2] Call Trace:
[ 9888.981833][ C2] ? snmp6_seq_show+0x180/0x180
[ 9888.981834][ C2] proc_create_single_data+0x7c/0xa0
[ 9888.981835][ C2] snmp6_register_dev+0xb0/0x130
[ 9888.981836][ C2] ipv6_add_dev+0x4b7/0xf60
[ 9888.981837][ C2] addrconf_notify+0x684/0x1ca0
[ 9888.981838][ C2] ? __mutex_unlock_slowpath+0xd0/0x670
[ 9888.981839][ C2] ? kasan_unpoison_shadow+0x30/0x40
[ 9888.981840][ C2] ? wait_for_completion+0x250/0x250
[ 9888.981841][ C2] ? inet6_ifinfo_notify+0x100/0x100
[ 9888.981842][ C2] ? dropmon_net_event+0x227/0x410
[ 9888.981843][ C2] ? notifier_call_chain+0x90/0x160
[ 9888.981844][ C2] ? inet6_ifinfo_notify+0x100/0x100
[ 9888.981845][ C2] notifier_call_chain+0x90/0x160
[ 9888.981846][ C2] register_netdevice+0xbe5/0x1070
[ ... ]
Reported-by: syzbot+1d51c8b74efa4c44adeb@syzkaller.appspotmail.com
Fixes: e0a4b99773d3 ("hsr: use upper/lower device infrastructure")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rcu_read_unlock();
}
-static void hsr_del_ports(struct hsr_priv *hsr)
+void hsr_del_ports(struct hsr_priv *hsr)
{
struct hsr_port *port;
hsr_del_port(port);
}
-/* This has to be called after all the readers are gone.
- * Otherwise we would have to check the return value of
- * hsr_port_get_hsr().
- */
-static void hsr_dev_destroy(struct net_device *hsr_dev)
-{
- struct hsr_priv *hsr = netdev_priv(hsr_dev);
-
- hsr_debugfs_term(hsr);
- hsr_del_ports(hsr);
-
- del_timer_sync(&hsr->prune_timer);
- del_timer_sync(&hsr->announce_timer);
-
- hsr_del_self_node(hsr);
- hsr_del_nodes(&hsr->node_db);
-}
-
static const struct net_device_ops hsr_device_ops = {
.ndo_change_mtu = hsr_dev_change_mtu,
.ndo_open = hsr_dev_open,
.ndo_stop = hsr_dev_close,
.ndo_start_xmit = hsr_dev_xmit,
.ndo_fix_features = hsr_fix_features,
- .ndo_uninit = hsr_dev_destroy,
};
static struct device_type hsr_type = {
#include <linux/netdevice.h>
#include "hsr_main.h"
+void hsr_del_ports(struct hsr_priv *hsr);
void hsr_dev_setup(struct net_device *dev);
int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
unsigned char multicast_spec, u8 protocol_version,
void hsr_check_carrier_and_operstate(struct hsr_priv *hsr);
bool is_hsr_master(struct net_device *dev);
int hsr_get_max_mtu(struct hsr_priv *hsr);
-
#endif /* __HSR_DEVICE_H */
*/
#include <linux/netdevice.h>
+#include <net/rtnetlink.h>
#include <linux/rculist.h>
#include <linux/timer.h>
#include <linux/etherdevice.h>
master = hsr_port_get_hsr(port->hsr, HSR_PT_MASTER);
hsr_del_port(port);
if (hsr_slave_empty(master->hsr)) {
- unregister_netdevice_queue(master->dev,
- &list_kill);
+ const struct rtnl_link_ops *ops;
+
+ ops = master->dev->rtnl_link_ops;
+ ops->dellink(master->dev, &list_kill);
unregister_netdevice_many(&list_kill);
}
}
static void __exit hsr_exit(void)
{
- unregister_netdevice_notifier(&hsr_nb);
hsr_netlink_exit();
hsr_debugfs_remove_root();
+ unregister_netdevice_notifier(&hsr_nb);
}
module_init(hsr_init);
return hsr_dev_finalize(dev, link, multicast_spec, hsr_version, extack);
}
+static void hsr_dellink(struct net_device *dev, struct list_head *head)
+{
+ struct hsr_priv *hsr = netdev_priv(dev);
+
+ del_timer_sync(&hsr->prune_timer);
+ del_timer_sync(&hsr->announce_timer);
+
+ hsr_debugfs_term(hsr);
+ hsr_del_ports(hsr);
+
+ hsr_del_self_node(hsr);
+ hsr_del_nodes(&hsr->node_db);
+
+ unregister_netdevice_queue(dev, head);
+}
+
static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
struct hsr_priv *hsr = netdev_priv(dev);
.priv_size = sizeof(struct hsr_priv),
.setup = hsr_dev_setup,
.newlink = hsr_newlink,
+ .dellink = hsr_dellink,
.fill_info = hsr_fill_info,
};