6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stanislav Fomichev sdf@fomichev.me
[ Upstream commit c64237960819aee1766d03f446ae6de94b1e3f73 ]
Syzkaller managed to trigger lock dependency in xsk_notify via register_netdevice. As discussed in [0], using register_netdevice in the notifiers is problematic so skip adding hamradio for ops-locked devices.
xsk_notifier+0x89/0x230 net/xdp/xsk.c:1664 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] unregister_netdevice_many_notify+0x14d7/0x1ff0 net/core/dev.c:12156 unregister_netdevice_many net/core/dev.c:12219 [inline] unregister_netdevice_queue+0x33c/0x380 net/core/dev.c:12063 register_netdevice+0x1689/0x1ae0 net/core/dev.c:11241 bpq_new_device drivers/net/hamradio/bpqether.c:481 [inline] bpq_device_event+0x491/0x600 drivers/net/hamradio/bpqether.c:523 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9608 dev_change_flags+0x130/0x260 net/core/dev_api.c:68 devinet_ioctl+0xbb4/0x1b50 net/ipv4/devinet.c:1200 inet_ioctl+0x3c0/0x4c0 net/ipv4/af_inet.c:1001
0: https://lore.kernel.org/netdev/20250625140357.6203d0af@kernel.org/ Fixes: 4c975fd70002 ("net: hold instance lock during NETDEV_REGISTER/UP") Suggested-by: Jakub Kicinski kuba@kernel.org Reported-by: syzbot+e6300f66a999a6612477@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=e6300f66a999a6612477 Signed-off-by: Stanislav Fomichev sdf@fomichev.me Link: https://patch.msgid.link/20250806213726.1383379-2-sdf@fomichev.me Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/hamradio/bpqether.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/hamradio/bpqether.c b/drivers/net/hamradio/bpqether.c index 0e0fe32d2da4..045c5177262e 100644 --- a/drivers/net/hamradio/bpqether.c +++ b/drivers/net/hamradio/bpqether.c @@ -138,7 +138,7 @@ static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
static inline int dev_is_ethdev(struct net_device *dev) { - return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); + return dev->type == ARPHRD_ETHER && !netdev_need_ops_lock(dev); }
/* ------------------------------------------------------------------------ */