EXT4-fs (loop3): VFS: Can't find ext4 filesystem INFO: task syz-executor4:8322 blocked for more than 120 seconds. Not tainted 4.17.0+ #86 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D21736 8322 4566 0x80000002 Call Trace: context_switch kernel/sched/core.c:2856 [inline] __schedule+0x801/0x1e30 kernel/sched/core.c:3498 schedule+0xef/0x430 kernel/sched/core.c:3542 __rwsem_down_write_failed_common+0x919/0x15d0 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+0xa2/0x120 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+0x494/0x12e0 drivers/tty/tty_io.c:1656 __fput+0x353/0x890 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1e4/0x290 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1aee/0x2730 kernel/exit.c:865 INFO: rcu_sched detected stalls on CPUs/tasks: 0-....: (125001 ticks this GP) idle=ebe/1/4611686018427387904 softirq=26319/26319 fqs=31150 (detected by 1, t=125003 jiffies, g=14399, c=14398, q=723) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 4.17.0+ #86 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 ff 94 88 7e 48 RSP: 0018:ffff8801d9a9f248 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000281210920 RCX: ffffffff83996c37 RDX: fffffffd7edf00e0 RSI: 0000000000000edf RDI: 0000000000000007 RBP: ffff8801d9a9f248 R08: ffff8801d9a921c0 R09: 0000000000000006 R10: ffff8801d9a921c0 R11: 0000000000000000 R12: ffffc9000279e000 R13: 0000000000000a00 R14: fffffffd7edf00e0 R15: 00000000000000ff FS: 0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f67b4deddb8 CR3: 0000000008c6a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: __sanitizer_cov_trace_const_cmp8+0x18/0x20 kernel/kcov.c:195 __process_echoes+0x277/0x8d0 drivers/tty/n_tty.c:731 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+0x2048/0x2c50 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+0x110/0x170 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:475 [inline] flush_to_ldisc+0x3e9/0x560 drivers/tty/tty_buffer.c:524 process_one_work+0xc64/0x1b70 kernel/workqueue.c:2153 worker_thread+0x181/0x13a0 kernel/workqueue.c:2296 kthread+0x345/0x410 kernel/kthread.c:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 do_group_exit+0x16f/0x430 kernel/exit.c:968 get_signal+0x886/0x1960 kernel/signal.c:2478 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810 exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455a09 Code: ac 24 38 01 00 00 48 81 c4 40 01 00 00 c3 c6 84 24 60 01 00 00 00 48 8b ac 24 38 01 00 00 48 81 c4 40 01 00 00 c3 c6 84 24 60 <01> 00 00 01 48 8b ac 24 38 01 00 00 48 81 c4 40 01 00 00 c3 c6 84 RSP: 002b:00007f67b4dedce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000072c028 RCX: 0000000000455a09 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072c028 RBP: 000000000072c028 R08: 0000000000000000 R09: 000000000072c000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffec7cfacdf R14: 00007f67b4dee9c0 R15: 0000000000000002 Showing all locks held in the system: 6 locks held by kworker/u4:0/7: 2 locks held by khungtaskd/894: #0: 00000000600f6890 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000600f6890 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 00000000600f6890 (rcu_read_lock){....}, at: debug_show_all_locks+0xc8/0x40c kernel/locking/lockdep.c:4461 1 lock held by rsyslogd/4392: 2 locks held by getty/4482: #0: 00000000d32db2d8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000056005bdf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4483: #0: 00000000845c5eb0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000d25207f4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4484: #0: 000000007b6aacb1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000097aa8528 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4485: #0: 00000000b842675d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ed85aead (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4486: #0: 0000000023191e0b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000014bfed53 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4487: #0: 000000003fcaeebd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000f4174133 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4488: #0: 000000006dfecdc5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000075961b41 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 4 locks held by syz-executor4/8322: #0: 00000000382bdf5e (&tty->legacy_mutex){+.+.}, at: tty_lock+0x70/0xa0 drivers/tty/tty_mutex.c:19 #1: 00000000424601ec (&tty->legacy_mutex/1){+.+.}, at: tty_lock+0x70/0xa0 drivers/tty/tty_mutex.c:19 #2: 00000000ecd2954a (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x22/0x90 drivers/tty/tty_ldisc.c:284 #3: 000000007c8d116b (&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: 894 Comm: khungtaskd Not tainted 4.17.0+ #86 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+0x1b9/0x294 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_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0xc10/0xf60 kernel/hung_task.c:249 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: 7 Comm: kworker/u4:0 Not tainted 4.17.0+ #86 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc RIP: 0010:__process_echoes+0x258/0x8d0 drivers/tty/n_tty.c:736 Code: 85 02 06 00 00 47 0f b6 b4 34 60 12 00 00 bf 82 ff ff ff 44 89 f6 e8 87 ed df fd 41 80 fe 82 0f 84 4f 05 00 00 e8 a8 ec df fd <4c> 8d 73 02 4c 89 f3 e8 9c ec df fd 4d 89 ee bf df 0e 00 00 49 29 RSP: 0018:ffff8801d9a9f268 EFLAGS: 00000293 RAX: ffff8801d9a921c0 RBX: 0000000284e2b0ac RCX: ffffffff83996c09 RDX: 0000000000000000 RSI: ffffffff83996c18 RDI: 0000000000000001 RBP: ffff8801d9a9f2d0 R08: ffff8801d9a921c0 R09: 0000000000000006 R10: ffff8801d9a921c0 R11: 0000000000000000 R12: ffffc9000279e000 R13: 0000000000000a00 R14: 0000000000000000 R15: 00000000000000ff FS: 0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f67b4deddb8 CR3: 0000000008c6a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: 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+0x2048/0x2c50 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+0x110/0x170 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:475 [inline] flush_to_ldisc+0x3e9/0x560 drivers/tty/tty_buffer.c:524 process_one_work+0xc64/0x1b70 kernel/workqueue.c:2153 worker_thread+0x181/0x13a0 kernel/workqueue.c:2296 kthread+0x345/0x410 kernel/kthread.c:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412