====================================================== WARNING: possible circular locking dependency detected 5.5.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/7312 is trying to acquire lock: ffff8880a4447528 ((wq_completion)wg-kex-wireguard0){+.+.}, at: flush_workqueue+0xee/0x1820 kernel/workqueue.c:2775 but task is already holding lock: ffff888076840e80 (&wg->static_identity.lock){++++}, at: wg_set_device+0xad0/0x2010 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){++++}: lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484 down_read+0x39/0x50 kernel/locking/rwsem.c:1495 wg_noise_handshake_create_initiation+0x6a/0x15c0 drivers/net/wireguard/noise.c:499 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline] wg_packet_handshake_send_worker+0xe5/0x1a0 drivers/net/wireguard/send.c:51 process_one_work+0x7f5/0x10f0 kernel/workqueue.c:2264 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 -> #1 ((work_completion)(&peer->transmit_handshake_work)){+.+.}: lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484 process_one_work+0x7c8/0x10f0 kernel/workqueue.c:2240 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 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:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain+0x1507/0x7be0 kernel/locking/lockdep.c:2970 __lock_acquire+0xc5a/0x1bc0 kernel/locking/lockdep.c:3954 lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484 flush_workqueue+0x10a/0x1820 kernel/workqueue.c:2775 peer_remove_after_dead+0x125/0x280 drivers/net/wireguard/peer.c:141 wg_peer_remove+0x211/0x270 drivers/net/wireguard/peer.c:176 wg_set_device+0xb6a/0x2010 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+0xf15/0x13e0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x19e/0x3e0 net/netlink/af_netlink.c:2477 genl_rcv+0x28/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x766/0x920 net/netlink/af_netlink.c:1328 netlink_sendmsg+0xa2b/0xd40 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x4f7/0x7f0 net/socket.c:2343 ___sys_sendmsg net/socket.c:2397 [inline] __sys_sendmsg+0x1ed/0x290 net/socket.c:2430 __do_sys_sendmsg net/socket.c:2439 [inline] __se_sys_sendmsg net/socket.c:2437 [inline] __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2437 do_syscall_64+0xf7/0x1c0 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.0/7312: #0: ffffffff895a4f00 (cb_lock){++++}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:744 #1: ffffffff895a4e28 (genl_mutex){+.+.}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffffffff895a4e28 (genl_mutex){+.+.}, at: genl_rcv_msg+0xca/0x13e0 net/netlink/genetlink.c:732 #2: ffffffff89590b20 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 #3: ffff8880768410a0 (&wg->device_update_lock){+.+.}, at: wg_set_device+0x3dd/0x2010 drivers/net/wireguard/netlink.c:510 #4: ffff888076840e80 (&wg->static_identity.lock){++++}, at: wg_set_device+0xad0/0x2010 drivers/net/wireguard/netlink.c:567 stack backtrace: CPU: 0 PID: 7312 Comm: syz-executor.0 Not tainted 5.5.0-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+0x1fb/0x318 lib/dump_stack.c:118 print_circular_bug+0xc3f/0xe70 kernel/locking/lockdep.c:1684 check_noncircular+0x206/0x3a0 kernel/locking/lockdep.c:1808 check_prev_add kernel/locking/lockdep.c:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain+0x1507/0x7be0 kernel/locking/lockdep.c:2970 __lock_acquire+0xc5a/0x1bc0 kernel/locking/lockdep.c:3954 lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484 flush_workqueue+0x10a/0x1820 kernel/workqueue.c:2775 peer_remove_after_dead+0x125/0x280 drivers/net/wireguard/peer.c:141 wg_peer_remove+0x211/0x270 drivers/net/wireguard/peer.c:176 wg_set_device+0xb6a/0x2010 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+0xf15/0x13e0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x19e/0x3e0 net/netlink/af_netlink.c:2477 genl_rcv+0x28/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x766/0x920 net/netlink/af_netlink.c:1328 netlink_sendmsg+0xa2b/0xd40 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x4f7/0x7f0 net/socket.c:2343 ___sys_sendmsg net/socket.c:2397 [inline] __sys_sendmsg+0x1ed/0x290 net/socket.c:2430 __do_sys_sendmsg net/socket.c:2439 [inline] __se_sys_sendmsg net/socket.c:2437 [inline] __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2437 do_syscall_64+0xf7/0x1c0 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:00007f5143a24c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5143a256d4 RCX: 000000000045b399 RDX: 0000000000000000 RSI: 0000000020001340 RDI: 0000000000000006 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000009bb R14: 00000000004cb2c4 R15: 000000000075bf2c