====================================================== WARNING: possible circular locking dependency detected 4.14.284-syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:1/22 is trying to acquire lock: ((&(&cp->cp_send_w)->work)){+.+.}, at: [] flush_work+0x88/0x770 kernel/workqueue.c:2887 but task is already holding lock: (k-sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1473 [inline] (k-sk_lock-AF_INET){+.+.}, at: [] rds_tcp_reset_callbacks+0x181/0x450 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_sock_nested+0xb7/0x100 net/core/sock.c:2813 lock_sock include/net/sock.h:1473 [inline] do_tcp_setsockopt.constprop.0+0xfb/0x1c10 net/ipv4/tcp.c:2564 tcp_setsockopt net/ipv4/tcp.c:2832 [inline] tcp_setsockopt+0xa7/0xc0 net/ipv4/tcp.c:2824 kernel_setsockopt+0xfb/0x1b0 net/socket.c:3396 rds_tcp_cork net/rds/tcp_send.c:43 [inline] rds_tcp_xmit_path_prepare+0xaf/0xe0 net/rds/tcp_send.c:50 rds_send_xmit+0x1ae/0x1c00 net/rds/send.c:187 rds_send_worker+0x6d/0x240 net/rds/threads.c:189 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #0 ((&(&cp->cp_send_w)->work)){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 flush_work+0xad/0x770 kernel/workqueue.c:2890 __cancel_work_timer+0x321/0x460 kernel/workqueue.c:2965 rds_tcp_reset_callbacks+0x18d/0x450 net/rds/tcp.c:167 rds_tcp_accept_one+0x61a/0x8b0 net/rds/tcp_listen.c:194 rds_tcp_accept_worker+0x4d/0x70 net/rds/tcp.c:407 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 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/u4:1/22: #0: ("%s""krdsd"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: ((&rtn->rds_tcp_accept_w)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 #2: (&tc->t_conn_path_lock){+.+.}, at: [] rds_tcp_accept_one+0x502/0x8b0 net/rds/tcp_listen.c:186 #3: (k-sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1473 [inline] #3: (k-sk_lock-AF_INET){+.+.}, at: [] rds_tcp_reset_callbacks+0x181/0x450 net/rds/tcp.c:165 stack backtrace: CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 4.14.284-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+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 flush_work+0xad/0x770 kernel/workqueue.c:2890 __cancel_work_timer+0x321/0x460 kernel/workqueue.c:2965 rds_tcp_reset_callbacks+0x18d/0x450 net/rds/tcp.c:167 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 rds_tcp_accept_one+0x61a/0x8b0 net/rds/tcp_listen.c:194 rds_tcp_accept_worker+0x4d/0x70 net/rds/tcp.c:407 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 IPv6: ADDRCONF(NETDEV_UP): batadv_slave_0: link is not ready kthread+0x30d/0x420 kernel/kthread.c:232 batman_adv: batadv0: Interface activated: batadv_slave_0 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): macsec0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready 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