batman_adv: batadv0: Interface activated: batadv_slave_1 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready ====================================================== WARNING: possible circular locking dependency detected 4.14.171-syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:14/8080 is trying to acquire lock: ((&(&cp->cp_send_w)->work)){+.+.}, at: [] flush_work+0x84/0x730 kernel/workqueue.c:2884 but task is already holding lock: (k-sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1467 [inline] (k-sk_lock-AF_INET){+.+.}, at: [] rds_tcp_reset_callbacks+0x18d/0x4a0 net/rds/tcp.c:165 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (k-sk_lock-AF_INET){+.+.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 lock_sock_nested+0xbd/0x110 net/core/sock.c:2770 lock_sock include/net/sock.h:1467 [inline] do_tcp_setsockopt.isra.0+0x11a/0x1e10 net/ipv4/tcp.c:2557 tcp_setsockopt+0xb3/0xd0 net/ipv4/tcp.c:2828 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:2968 kernel_setsockopt+0x104/0x1d0 net/socket.c:3396 rds_tcp_cork net/rds/tcp_send.c:43 [inline] rds_tcp_xmit_path_prepare+0xba/0xf0 net/rds/tcp_send.c:50 rds_send_xmit+0x1b2/0x1cd0 net/rds/send.c:187 rds_send_worker+0x73/0x250 net/rds/threads.c:189 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #0 ((&(&cp->cp_send_w)->work)){+.+.}: check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 flush_work+0xae/0x730 kernel/workqueue.c:2887 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2962 cancel_delayed_work_sync+0x1b/0x20 kernel/workqueue.c:3082 rds_tcp_reset_callbacks+0x19a/0x4a0 net/rds/tcp.c:167 rds_tcp_accept_one+0x682/0xa10 net/rds/tcp_listen.c:194 rds_tcp_accept_worker+0x53/0x70 net/rds/tcp.c:407 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(k-sk_lock-AF_INET); lock((&(&cp->cp_send_w)->work)); lock(k-sk_lock-AF_INET); lock((&(&cp->cp_send_w)->work)); *** DEADLOCK *** 4 locks held by kworker/u4:14/8080: #0: ("%s""krdsd"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("%s""krdsd"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("%s""krdsd"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("%s""krdsd"){+.+.}, at: [] process_one_work+0x76e/0x1600 kernel/workqueue.c:2085 #1: ((&rtn->rds_tcp_accept_w)){+.+.}, at: [] process_one_work+0x7ab/0x1600 kernel/workqueue.c:2089 #2: (&tc->t_conn_path_lock){+.+.}, at: [] rds_tcp_accept_one+0x548/0xa10 net/rds/tcp_listen.c:186 #3: (k-sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1467 [inline] #3: (k-sk_lock-AF_INET){+.+.}, at: [] rds_tcp_reset_callbacks+0x18d/0x4a0 net/rds/tcp.c:165 stack backtrace: CPU: 0 PID: 8080 Comm: kworker/u4:14 Not tainted 4.14.171-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: krdsd rds_tcp_accept_worker Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 flush_work+0xae/0x730 kernel/workqueue.c:2887 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2962 cancel_delayed_work_sync+0x1b/0x20 kernel/workqueue.c:3082 rds_tcp_reset_callbacks+0x19a/0x4a0 net/rds/tcp.c:167 rds_tcp_accept_one+0x682/0xa10 net/rds/tcp_listen.c:194 rds_tcp_accept_worker+0x53/0x70 net/rds/tcp.c:407 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404