INFO: task syz-executor.0:27409 blocked for more than 143 seconds. Not tainted 5.6.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28328 27409 9562 0x80004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4154 schedule_timeout+0x6db/0xba0 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x26a/0x3c0 kernel/sched/completion.c:136 io_queue_file_removal+0x1af/0x1e0 fs/io_uring.c:5840 __io_sqe_files_update.isra.0+0x3a1/0xb00 fs/io_uring.c:5881 io_sqe_files_update fs/io_uring.c:5932 [inline] __io_uring_register+0x377/0x2c00 fs/io_uring.c:7145 __do_sys_io_uring_register fs/io_uring.c:7216 [inline] __se_sys_io_uring_register fs/io_uring.c:7198 [inline] __x64_sys_io_uring_register+0x192/0x560 fs/io_uring.c:7198 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: Bad RIP value. RSP: 002b:00007f20b2763c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 00007f20b27646d4 RCX: 000000000045c849 RDX: 0000000020000300 RSI: 0000000000000006 RDI: 0000000000000003 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000005 R13: 00000000000001fe R14: 00000000004d2f40 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/1132: #0: ffffffff897accc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5331 1 lock held by rsyslogd/9434: #0: ffff8880952e5ba0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:826 2 locks held by getty/9524: #0: ffff8880a07f8090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000172b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9525: #0: ffff888098509090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017bb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9526: #0: ffff8880a80a7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000176b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9527: #0: ffff888097b59090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017872e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9528: #0: ffff8880a40c2090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000179b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9529: #0: ffff8880a8ed2090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900017ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/9530: #0: ffff88809a73b090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000170b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 7 locks held by kworker/u4:0/23281: 1 lock held by syz-executor.0/27409: #0: ffff888091e1b320 (&ctx->uring_lock){+.+.}, at: __do_sys_io_uring_register fs/io_uring.c:7215 [inline] #0: ffff888091e1b320 (&ctx->uring_lock){+.+.}, at: __se_sys_io_uring_register fs/io_uring.c:7198 [inline] #0: ffff888091e1b320 (&ctx->uring_lock){+.+.}, at: __x64_sys_io_uring_register+0x181/0x560 fs/io_uring.c:7198 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1132 Comm: khungtaskd Not tainted 5.6.0-rc6-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 23281 Comm: kworker/u4:0 Not tainted 5.6.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: krdsd rds_connect_worker RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:153 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x50 kernel/kcov.c:187 Code: cc 65 48 8b 04 25 c0 1e 02 00 48 8b 80 98 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 65 48 8b 04 25 c0 1e 02 00 <65> 8b 15 58 f9 8f 7e 81 e2 00 01 1f 00 48 8b 34 24 75 2b 8b 90 80 RSP: 0018:ffffc90000006f78 EFLAGS: 00000206 RAX: ffff88804b7d24c0 RBX: ffff8880a7d48000 RCX: 0000000000000000 RDX: 0000000000000100 RSI: ffffffff860fb59f RDI: ffff88802bd34102 RBP: ffffc90000007110 R08: ffff88804b7d24c0 R09: ffffed1015cc7074 R10: ffffed1015cc7073 R11: ffff8880ae63839b R12: ffff88802bd34080 R13: ffff8880a7d482c0 R14: 000000000000004a R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000045c81f CR3: 00000000942d0000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __dev_queue_xmit+0x764/0x30a0 net/core/dev.c:4011 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip_finish_output2+0x17b7/0x2610 net/ipv4/ip_output.c:228 __ip_finish_output net/ipv4/ip_output.c:306 [inline] __ip_finish_output+0x5f3/0xbd0 net/ipv4/ip_output.c:288 ip_finish_output+0x34/0x1f0 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x1fe/0x620 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:436 [inline] ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:125 tcp_v4_send_synack+0x222/0x460 net/ipv4/tcp_ipv4.c:976 tcp_conn_request+0x2548/0x34c0 net/ipv4/tcp_input.c:6719 tcp_v4_conn_request net/ipv4/tcp_ipv4.c:1451 [inline] tcp_v4_conn_request+0xbc/0x240 net/ipv4/tcp_ipv4.c:1445 tcp_v6_conn_request+0x1ed/0x2b0 net/ipv6/tcp_ipv6.c:1146 tcp_rcv_state_process+0xa27/0x52ca net/ipv4/tcp_input.c:6190 tcp_v4_do_rcv+0x34c/0x8b0 net/ipv4/tcp_ipv4.c:1641 tcp_v4_rcv+0x33aa/0x3870 net/ipv4/tcp_ipv4.c:1989 ip_protocol_deliver_rcu+0x57/0x880 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x220/0x360 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip_local_deliver+0x1c8/0x4e0 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x1da/0x2f0 net/ipv4/ip_input.c:428 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip_rcv+0xd0/0x3c0 net/ipv4/ip_input.c:538 __netif_receive_skb_one_core+0xf5/0x160 net/core/dev.c:5187 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5301 process_backlog+0x21e/0x7a0 net/core/dev.c:6133 napi_poll net/core/dev.c:6571 [inline] net_rx_action+0x4c2/0x1070 net/core/dev.c:6639 __do_softirq+0x26c/0x99d kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082 do_softirq.part.0+0x10f/0x160 kernel/softirq.c:337 do_softirq kernel/softirq.c:329 [inline] __local_bh_enable_ip+0x20e/0x270 kernel/softirq.c:189 local_bh_enable include/linux/bottom_half.h:32 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:690 [inline] ip_finish_output2+0x957/0x2610 net/ipv4/ip_output.c:229 __ip_finish_output net/ipv4/ip_output.c:306 [inline] __ip_finish_output+0x5f3/0xbd0 net/ipv4/ip_output.c:288 ip_finish_output+0x34/0x1f0 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x1fe/0x620 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:436 [inline] ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:125 __ip_queue_xmit+0x863/0x1c20 net/ipv4/ip_output.c:530 __tcp_transmit_skb+0x19d6/0x3740 net/ipv4/tcp_output.c:1234 tcp_transmit_skb net/ipv4/tcp_output.c:1250 [inline] tcp_connect+0x2d06/0x42a0 net/ipv4/tcp_output.c:3657 tcp_v4_connect+0x14f0/0x1c10 net/ipv4/tcp_ipv4.c:311 __inet_stream_connect+0x80f/0xe30 net/ipv4/af_inet.c:655 inet_stream_connect+0x53/0xa0 net/ipv4/af_inet.c:719 rds_tcp_conn_path_connect+0x620/0x880 net/rds/tcp_connect.c:172 rds_connect_worker+0x1a5/0x2c0 net/rds/threads.c:176 process_one_work+0x94b/0x1690 kernel/workqueue.c:2266 worker_thread+0x96/0xe20 kernel/workqueue.c:2412 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352