device lo left promiscuous mode device lo entered promiscuous mode INFO: task syz-executor1:14459 blocked for more than 120 seconds. Not tainted 4.18.0-rc2+ #124 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D22200 14459 9774 0x80000002 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x87c/0x1ed0 kernel/sched/core.c:3504 schedule+0xfb/0x450 kernel/sched/core.c:3548 __rwsem_down_write_failed_common+0x95d/0x1630 kernel/locking/rwsem-xadd.c:566 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0xaa/0x130 kernel/locking/rwsem.c:72 n_tty_flush_buffer+0x21/0x320 drivers/tty/n_tty.c:357 tty_ldisc_hangup+0x89/0x640 drivers/tty/tty_ldisc.c:711 __tty_hangup.part.21+0x2da/0x6e0 drivers/tty/tty_io.c:621 __tty_hangup drivers/tty/tty_io.c:571 [inline] tty_vhangup+0x21/0x30 drivers/tty/tty_io.c:694 pty_close+0x3bd/0x510 drivers/tty/pty.c:78 tty_release+0x4b3/0x1300 drivers/tty/tty_io.c:1665 __fput+0x355/0x8b0 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1b08/0x2750 kernel/exit.c:865 do_group_exit+0x177/0x440 kernel/exit.c:968 get_signal+0x88e/0x1970 kernel/signal.c:2468 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455a99 Code: 47 48 00 48 89 04 24 48 c7 44 24 08 1d 00 00 00 e8 8c 71 fd ff e8 37 6a fd ff 0f b6 44 24 2f 83 e0 1f 48 89 04 24 e8 b6 6f fd e8 81 6a fd ff e8 5c 68 fd ff 48 8d 05 93 47 48 00 48 89 04 24 RSP: 002b:00007f29b4ab3ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000072c0b8 RCX: 0000000000455a99 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072c0b8 RBP: 000000000072c0b8 R08: 0000000000000000 R09: 000000000072c098 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff811f255f R14: 00007f29b4ab49c0 R15: 0000000000000003 Showing all locks held in the system: 1 lock held by khungtaskd/898: #0: 00000000392e8705 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4428: 2 locks held by getty/4518: #0: 00000000dfa8f988 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000007e29753f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4519: #0: 0000000090013750 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000425b86c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4520: #0: 000000000394a95e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000be12980a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4521: #0: 000000008da3e026 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000778f5f08 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4522: #0: 00000000f5501d9b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000dee3bcfa (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4523: #0: 00000000dc2cbbc0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000063eae64e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 2 locks held by getty/4524: #0: 0000000071355f2c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003c83d4b6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2131 3 locks held by kworker/0:4/4985: 6 locks held by kworker/u4:5/6948: 4 locks held by syz-executor1/14459: #0: 00000000e57957d0 (&tty->legacy_mutex){+.+.}, at: tty_lock+0x70/0xa0 drivers/tty/tty_mutex.c:19 #1: 00000000e9b8b16c (&tty->legacy_mutex/1){+.+.}, at: tty_lock+0x70/0xa0 drivers/tty/tty_mutex.c:19 #2: 00000000584ec26d (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x22/0x90 drivers/tty/tty_ldisc.c:284 #3: 000000006b884057 (&o_tty->termios_rwsem/1){++++}, at: n_tty_flush_buffer+0x21/0x320 drivers/tty/n_tty.c:357 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 898 Comm: khungtaskd Not tainted 4.18.0-rc2+ #124 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+0x1c9/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x9c4/0xf80 kernel/hung_task.c:252 kthread+0x345/0x410 kernel/kthread.c:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6948 Comm: kworker/u4:5 Not tainted 4.18.0-rc2+ #124 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc RIP: 0010:__write_once_size include/linux/compiler.h:215 [inline] RIP: 0010:write_comp_data+0x6c/0x70 kernel/kcov.c:144 Code: 00 00 4e 8d 14 dd 28 00 00 00 4d 39 d0 72 1b 49 83 c1 01 4a 89 7c 10 e0 4a 89 74 10 e8 4a 89 54 10 f0 4a 89 4c d8 20 4c 89 08 <5d> c3 66 90 55 65 48 8b 04 25 40 ee 01 00 65 8b 15 4f e1 85 7e 48 RSP: 0018:ffff88019a777228 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 00000002b9e064c2 RCX: ffffffff83a456e9 RDX: 0000000000000000 RSI: 0000000000000082 RDI: 0000000000000001 RBP: ffff88019a777228 R08: ffff8801d8b0a300 R09: 0000000000000006 R10: ffff8801d8b0a300 R11: 0000000000000000 R12: ffffc9000cd79000 R13: 0000000000001000 R14: 0000000000000000 R15: 00000000000000ff FS: 0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f29b4ab3db8 CR3: 0000000008e6a000 CR4: 00000000001406f0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: __sanitizer_cov_trace_const_cmp1+0x1a/0x20 kernel/kcov.c:174 __process_echoes+0x249/0x8d0 drivers/tty/n_tty.c:733 commit_echoes+0x163/0x1d0 drivers/tty/n_tty.c:764 n_tty_receive_char_fast drivers/tty/n_tty.c:1416 [inline] n_tty_receive_buf_fast drivers/tty/n_tty.c:1576 [inline] __receive_buf drivers/tty/n_tty.c:1611 [inline] n_tty_receive_buf_common+0x205b/0x2c60 drivers/tty/n_tty.c:1709 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1744 tty_ldisc_receive_buf+0xb0/0x190 drivers/tty/tty_buffer.c:456 tty_port_default_receive_buf+0x115/0x180 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:475 [inline] flush_to_ldisc+0x3fd/0x570 drivers/tty/tty_buffer.c:524 process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 kthread+0x345/0x410 kernel/kthread.c:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412