============================================ WARNING: possible recursive locking detected 5.8.0-rc2-syzkaller #0 Not tainted -------------------------------------------- syz-executor.2/15673 is trying to acquire lock: ffff88809dc78280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: netif_addr_lock_nested include/linux/netdevice.h:4243 [inline] ffff88809dc78280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: dev_mc_unsync net/core/dev_addr_lists.c:915 [inline] ffff88809dc78280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: dev_mc_unsync+0xf4/0x190 net/core/dev_addr_lists.c:909 but task is already holding lock: ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:358 [inline] ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: netif_addr_lock_bh include/linux/netdevice.h:4248 [inline] ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: dev_mc_unsync net/core/dev_addr_lists.c:914 [inline] ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: dev_mc_unsync+0xb0/0x190 net/core/dev_addr_lists.c:909 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&vlan_netdev_addr_lock_key/1); lock(&vlan_netdev_addr_lock_key/1); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by syz-executor.2/15673: #0: ffffffff8a809c30 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:763 #1: ffffffff8a809ce8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffffffff8a809ce8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x76a/0x9e0 net/netlink/genetlink.c:751 #2: ffffffff8a7d13c8 (devlink_mutex){+.+.}-{3:3}, at: devlink_nl_pre_doit+0x27/0x6a0 net/core/devlink.c:405 #3: ffff88809b8de370 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_port_del_all drivers/net/netdevsim/dev.c:951 [inline] #3: ffff88809b8de370 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_reload_destroy+0x9e/0x1e0 drivers/net/netdevsim/dev.c:1130 #4: ffffffff8a7b00e8 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x2b/0x60 drivers/net/netdevsim/netdev.c:329 #5: ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:358 [inline] #5: ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: netif_addr_lock_bh include/linux/netdevice.h:4248 [inline] #5: ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: dev_mc_unsync net/core/dev_addr_lists.c:914 [inline] #5: ffff88808f4dc280 (&vlan_netdev_addr_lock_key/1){+...}-{2:2}, at: dev_mc_unsync+0xb0/0x190 net/core/dev_addr_lists.c:909 stack backtrace: CPU: 1 PID: 15673 Comm: syz-executor.2 Not tainted 5.8.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:2391 [inline] check_deadlock kernel/locking/lockdep.c:2432 [inline] validate_chain kernel/locking/lockdep.c:3202 [inline] __lock_acquire.cold+0x178/0x3f8 kernel/locking/lockdep.c:4380 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:4959 _raw_spin_lock_nested+0x30/0x40 kernel/locking/spinlock.c:361 netif_addr_lock_nested include/linux/netdevice.h:4243 [inline] dev_mc_unsync net/core/dev_addr_lists.c:915 [inline] dev_mc_unsync+0xf4/0x190 net/core/dev_addr_lists.c:909 vlan_dev_stop+0x51/0x350 net/8021q/vlan_dev.c:315 __dev_close_many+0x1b3/0x2e0 net/core/dev.c:1605 dev_close_many+0x238/0x650 net/core/dev.c:1630 rollback_registered_many+0x3af/0xf60 net/core/dev.c:8953 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10121 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10120 vlan_device_event+0x1ab5/0x2010 net/8021q/vlan.c:490 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2033 call_netdevice_notifiers_extack net/core/dev.c:2045 [inline] call_netdevice_notifiers net/core/dev.c:2059 [inline] rollback_registered_many+0x665/0xf60 net/core/dev.c:8976 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10121 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10120 vlan_device_event+0x1ab5/0x2010 net/8021q/vlan.c:490 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2033 call_netdevice_notifiers_extack net/core/dev.c:2045 [inline] call_netdevice_notifiers net/core/dev.c:2059 [inline] rollback_registered_many+0x665/0xf60 net/core/dev.c:8976 rollback_registered net/core/dev.c:9021 [inline] unregister_netdevice_queue+0x2dd/0x570 net/core/dev.c:10102 unregister_netdevice include/linux/netdevice.h:2754 [inline] nsim_destroy+0x35/0x60 drivers/net/netdevsim/netdev.c:330 __nsim_dev_port_del+0x144/0x1e0 drivers/net/netdevsim/dev.c:941 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:954 [inline] nsim_dev_reload_destroy+0xff/0x1e0 drivers/net/netdevsim/dev.c:1130 nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:711 devlink_reload+0xc1/0x3a0 net/core/devlink.c:2921 devlink_nl_cmd_reload+0x386/0x880 net/core/devlink.c:2956 genl_family_rcv_msg_doit net/netlink/genetlink.c:691 [inline] genl_family_rcv_msg net/netlink/genetlink.c:736 [inline] genl_rcv_msg+0x61d/0x9e0 net/netlink/genetlink.c:753 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2469 genl_rcv+0x24/0x40 net/netlink/genetlink.c:764 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1329 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2352 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f8d0757ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004fe320 RCX: 000000000045cb29 RDX: 0000000000000000 RSI: 0000000020000800 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000933 R14: 00000000004cc114 R15: 00007f8d0757f6d4