INFO: task kworker/u4:3:18088 blocked for more than 143 seconds. Not tainted 5.5.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:3 D25808 18088 2 0x80004000 Workqueue: events_unbound flush_to_ldisc Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x87f/0xcd0 kernel/sched/core.c:4082 schedule+0x188/0x210 kernel/sched/core.c:4156 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215 __mutex_lock_common+0x11f1/0x2f30 kernel/locking/mutex.c:1033 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 flush_to_ldisc+0x39/0x550 drivers/tty/tty_buffer.c:505 process_one_work+0x7f5/0x10f0 kernel/workqueue.c:2264 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 INFO: task syz-executor.1:24215 blocked for more than 143 seconds. Not tainted 5.5.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D27672 24215 9013 0x00004004 Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x87f/0xcd0 kernel/sched/core.c:4082 schedule+0x188/0x210 kernel/sched/core.c:4156 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215 __mutex_lock_common+0x11f1/0x2f30 kernel/locking/mutex.c:1033 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 tty_buffer_lock_exclusive+0x33/0x40 drivers/tty/tty_buffer.c:61 paste_selection+0xf3/0x400 drivers/tty/vt/selection.c:361 tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3044 vt_ioctl+0x3f1/0x3a70 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0xee6/0x15c0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl fs/ioctl.c:763 [inline] __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl+0x113/0x190 fs/ioctl.c:770 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:770 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: Bad RIP value. RSP: 002b:00007fc60cbd9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fc60cbda6d4 RCX: 000000000045b399 RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000056c R14: 00000000004c6b4d R15: 000000000075bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1121: #0: ffffffff892d98c8 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 1 lock held by rsyslogd/8883: #0: ffff8880a4c0db60 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x279/0x310 fs/file.c:821 2 locks held by getty/8974: #0: ffff88808efe7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc9000196b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8975: #0: ffff88809dde4090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8976: #0: ffff888098e6c090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc9000198b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8977: #0: ffff88809686e090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8978: #0: ffff88808e150090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8979: #0: ffff88808efd1090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc9000192b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:3/18088: #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: process_one_work+0x763/0x10f0 kernel/workqueue.c:2237 #1: ffffc90001af7d78 ((work_completion)(&buf->work)){+.+.}, at: process_one_work+0x7a5/0x10f0 kernel/workqueue.c:2239 #2: ffff8880aa5be0a8 (&buf->lock){+.+.}, at: flush_to_ldisc+0x39/0x550 drivers/tty/tty_buffer.c:505 2 locks held by getty/24032: #0: ffff8880936bd198 (&tty->legacy_mutex){+.+.}, at: tty_lock+0xa6/0x110 drivers/tty/tty_mutex.c:19 #1: ffff8880936bd090 (&tty->ldisc_sem){++++}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:315 [inline] #1: ffff8880936bd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_lock+0x6e/0xb0 drivers/tty/tty_ldisc.c:339 4 locks held by syz-executor.4/24198: 2 locks held by syz-executor.1/24215: #0: ffff8880936bd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffff8880aa5be0a8 (&buf->lock){+.+.}, at: tty_buffer_lock_exclusive+0x33/0x40 drivers/tty/tty_buffer.c:61 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1121 Comm: khungtaskd Not tainted 5.5.0-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+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaa/0x190 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x16f/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace+0x17/0x20 include/linux/nmi.h:146 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd40/0xd60 kernel/hung_task.c:289 kthread+0x332/0x350 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: 24198 Comm: syz-executor.4 Not tainted 5.5.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:pvclock_clocksource_read+0x56/0x640 arch/x86/kernel/pvclock.c:68 Code: 57 10 48 83 c7 1d 4d 8d 5d 03 4c 89 ea 48 c1 ea 03 4c 89 d9 48 c1 e9 03 49 8d 58 07 4c 89 c0 48 c1 e8 03 48 89 85 68 ff ff ff <48> 89 d8 48 89 5d 88 48 c1 eb 03 48 89 9d 70 ff ff ff 49 8d 41 03 RSP: 0018:ffffc900057e7810 EFLAGS: 00000802 RAX: 1ffffffff133f001 RBX: ffffffff899f800f RCX: 1ffffffff133f000 RDX: 1ffffffff133f000 RSI: ffffffff899f801c RDI: ffffffff899f801d RBP: ffffc900057e78b0 R08: ffffffff899f8008 R09: ffffffff899f8018 R10: ffffffff899f8010 R11: ffffffff899f8003 R12: dffffc0000000000 R13: ffffffff899f8000 R14: 1ffff11015d46f89 R15: ffff8880aea37b60 FS: 00007fe1f84c6700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd1eaa49000 CR3: 0000000094737000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kvm_clock_read arch/x86/kernel/kvmclock.c:90 [inline] kvm_sched_clock_read+0x19/0x40 arch/x86/kernel/kvmclock.c:102 paravirt_sched_clock arch/x86/include/asm/paravirt.h:22 [inline] sched_clock+0x3a/0x40 arch/x86/kernel/tsc.c:245 sched_clock_cpu+0x1b/0x3d0 kernel/sched/clock.c:371 update_rq_clock+0xb3/0x430 kernel/sched/core.c:215 __schedule+0x14c/0xcd0 kernel/sched/core.c:4035 schedule+0x188/0x210 kernel/sched/core.c:4156 paste_selection+0x269/0x400 drivers/tty/vt/selection.c:367 tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3044 vt_ioctl+0x3f1/0x3a70 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0xee6/0x15c0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl fs/ioctl.c:763 [inline] __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl+0x113/0x190 fs/ioctl.c:770 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:770 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b399 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe1f84c5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe1f84c66d4 RCX: 000000000045b399 RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000056c R14: 00000000004c6b4d R15: 000000000075bf2c