====================================================== WARNING: possible circular locking dependency detected 5.5.0-rc1-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/8188 is trying to acquire lock: ffff88807e584d28 ((wq_completion)wg-kex-wireguard0){+.+.}, at: flush_workqueue+0xcf/0x13d0 kernel/workqueue.c:2772 but task is already holding lock: ffff88808fb74e80 (&wg->static_identity.lock){++++}, at: wg_set_device+0xcd8/0x1180 drivers/net/wireguard/netlink.c:567 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&wg->static_identity.lock){++++}: down_read+0x95/0x430 kernel/locking/rwsem.c:1495 wg_noise_handshake_create_initiation+0xc9/0x620 drivers/net/wireguard/noise.c:499 wg_packet_send_handshake_initiation+0x14a/0x200 drivers/net/wireguard/send.c:34 wg_packet_handshake_send_worker+0x14/0x20 drivers/net/wireguard/send.c:51 process_one_work+0x856/0x1630 kernel/workqueue.c:2264 worker_thread+0x85/0xb60 kernel/workqueue.c:2410 kthread+0x331/0x3f0 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 -> #1 ((work_completion)(&peer->transmit_handshake_work)){+.+.}: process_one_work+0x7f0/0x1630 kernel/workqueue.c:2240 worker_thread+0x85/0xb60 kernel/workqueue.c:2410 kthread+0x331/0x3f0 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 -> #0 ((wq_completion)wg-kex-wireguard0){+.+.}: check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2899/0x4ef0 kernel/locking/lockdep.c:3955 lock_acquire+0x194/0x410 kernel/locking/lockdep.c:4485 flush_workqueue+0xf2/0x13d0 kernel/workqueue.c:2775 peer_remove_after_dead+0x152/0x210 drivers/net/wireguard/peer.c:141 wg_peer_remove+0x209/0x2e0 drivers/net/wireguard/peer.c:176 wg_set_device+0xd96/0x1180 drivers/net/wireguard/netlink.c:575 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline] genl_family_rcv_msg net/netlink/genetlink.c:717 [inline] genl_rcv_msg+0x5d9/0x10e0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x13c/0x380 net/netlink/af_netlink.c:2477 genl_rcv+0x23/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x45e/0x6a0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x7b0/0xcb0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:659 ____sys_sendmsg+0x603/0x950 net/socket.c:2330 ___sys_sendmsg+0xe4/0x160 net/socket.c:2384 __sys_sendmsg+0xd9/0x180 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2424 do_syscall_64+0xca/0x5f0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: (wq_completion)wg-kex-wireguard0 --> (work_completion)(&peer->transmit_handshake_work) --> &wg->static_identity.lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&wg->static_identity.lock); lock((work_completion)(&peer->transmit_handshake_work)); lock(&wg->static_identity.lock); lock((wq_completion)wg-kex-wireguard0); *** DEADLOCK *** 5 locks held by syz-executor.3/8188: #0: ffffffff898924a8 (cb_lock){++++}, at: genl_rcv+0x14/0x40 net/netlink/genetlink.c:744 #1: ffffffff89892560 (genl_mutex){+.+.}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffffffff89892560 (genl_mutex){+.+.}, at: genl_rcv_msg+0x663/0x10e0 net/netlink/genetlink.c:732 #2: ffffffff898459a0 (rtnl_mutex){+.+.}, at: rtnl_lock+0x12/0x20 net/core/rtnetlink.c:72 #3: ffff88808fb750a0 (&wg->device_update_lock){+.+.}, at: wg_set_device+0x249/0x1180 drivers/net/wireguard/netlink.c:510 #4: ffff88808fb74e80 (&wg->static_identity.lock){++++}, at: wg_set_device+0xcd8/0x1180 drivers/net/wireguard/netlink.c:567 stack backtrace: CPU: 1 PID: 8188 Comm: syz-executor.3 Not tainted 5.5.0-rc1-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+0x12d/0x187 lib/dump_stack.c:118 print_circular_bug.isra.39.cold.58+0x15a/0x169 kernel/locking/lockdep.c:1685 check_noncircular+0x349/0x400 kernel/locking/lockdep.c:1809 check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2899/0x4ef0 kernel/locking/lockdep.c:3955 lock_acquire+0x194/0x410 kernel/locking/lockdep.c:4485 flush_workqueue+0xf2/0x13d0 kernel/workqueue.c:2775 peer_remove_after_dead+0x152/0x210 drivers/net/wireguard/peer.c:141 wg_peer_remove+0x209/0x2e0 drivers/net/wireguard/peer.c:176 wg_set_device+0xd96/0x1180 drivers/net/wireguard/netlink.c:575 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline] genl_family_rcv_msg net/netlink/genetlink.c:717 [inline] genl_rcv_msg+0x5d9/0x10e0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x13c/0x380 net/netlink/af_netlink.c:2477 genl_rcv+0x23/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x45e/0x6a0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x7b0/0xcb0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:659 ____sys_sendmsg+0x603/0x950 net/socket.c:2330 ___sys_sendmsg+0xe4/0x160 net/socket.c:2384 __sys_sendmsg+0xd9/0x180 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2424 do_syscall_64+0xca/0x5f0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fca2d4efc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fca2d4f06d4 RCX: 000000000045b399 RDX: 0000000000000000 RSI: 0000000020001340 RDI: 0000000000000004 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000009ba R14: 00000000004cb2b8 R15: 000000000075bfd4