INFO: task getty:9525 blocked for more than 143 seconds. Not tainted 5.6.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. getty D23896 9525 1 0x80000002 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 down_write_failed drivers/tty/tty_ldsem.c:262 [inline] __ldsem_down_write_nested+0x3b2/0x8f0 drivers/tty/tty_ldsem.c:324 ldsem_down_write+0x33/0x40 drivers/tty/tty_ldsem.c:366 __tty_ldisc_lock drivers/tty/tty_ldisc.c:315 [inline] tty_ldisc_lock+0x66/0xb0 drivers/tty/tty_ldisc.c:339 tty_ldisc_hangup+0x1c6/0x640 drivers/tty/tty_ldisc.c:745 __tty_hangup.part.0+0x2fb/0x750 drivers/tty/tty_io.c:625 __tty_hangup drivers/tty/tty_io.c:575 [inline] tty_vhangup_session+0x25/0x30 drivers/tty/tty_io.c:735 disassociate_ctty.part.0+0xb4/0x740 drivers/tty/tty_jobctrl.c:267 disassociate_ctty+0x81/0xa0 drivers/tty/tty_jobctrl.c:261 do_exit+0x1b82/0x2f50 kernel/exit.c:799 do_group_exit+0x135/0x360 kernel/exit.c:899 __do_sys_exit_group kernel/exit.c:910 [inline] __se_sys_exit_group kernel/exit.c:908 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:908 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f5b814971e8 Code: Bad RIP value. RSP: 002b:00007ffccb7c3408 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f5b814971e8 RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 RBP: 00007f5b8176c840 R08: 00000000000000e7 R09: ffffffffffffffa8 R10: 00007f5b81772740 R11: 0000000000000246 R12: 00007f5b8176c840 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 INFO: task kworker/u4:3:12496 blocked for more than 143 seconds. Not tainted 5.6.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:3 D26864 12496 2 0x80004000 Workqueue: events_unbound flush_to_ldisc Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4213 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 flush_to_ldisc+0x3d/0x390 drivers/tty/tty_buffer.c:505 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 1 lock held by khungtaskd/1132: #0: ffffffff89bac240 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333 1 lock held by rsyslogd/9435: #0: ffff8880a05bab20 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821 2 locks held by getty/9525: #0: ffff8880a2173198 (&tty->legacy_mutex){+.+.}, at: tty_lock+0xc7/0x130 drivers/tty/tty_mutex.c:19 #1: ffff8880a2173090 (&tty->ldisc_sem){++++}, at: ldsem_down_write+0x33/0x40 drivers/tty/tty_ldsem.c:366 2 locks held by getty/9526: #0: ffff8880a381d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000187b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9527: #0: ffff888090c96090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000186b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9528: #0: ffff888090c97090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000188b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9529: #0: ffff88809ec44090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000180b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9530: #0: ffff8880a6de6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000185b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9531: #0: ffff8880a7c51090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:3/12496: #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa433928 ((wq_completion)events_unbound){+.+.}, at: process_one_work+0x8dd/0x17a0 kernel/workqueue.c:2235 #1: ffffc90001f07dc0 ((work_completion)(&buf->work)){+.+.}, at: process_one_work+0x917/0x17a0 kernel/workqueue.c:2239 #2: ffff8880aa5be0a8 (&buf->lock){+.+.}, at: flush_to_ldisc+0x3d/0x390 drivers/tty/tty_buffer.c:505 3 locks held by syz-executor.4/16286: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1132 Comm: khungtaskd Not tainted 5.6.0-rc2-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 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: 12503 Comm: kworker/u4:7 Not tainted 5.6.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:check_memory_region+0x1f/0x1a0 mm/kasan/generic.c:191 Code: 00 66 2e 0f 1f 84 00 00 00 00 00 48 85 f6 0f 84 34 01 00 00 48 b8 ff ff ff ff ff 7f ff ff 55 0f b6 d2 48 39 c7 48 89 e5 41 55 <41> 54 53 0f 86 07 01 00 00 4c 8d 5c 37 ff 49 89 f8 48 b8 00 00 00 RSP: 0018:ffffc90000007be8 EFLAGS: 00000016 RAX: ffff7fffffffffff RBX: 0000000000000000 RCX: ffffffff815ae1d4 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8b519c10 RBP: ffffc90000007bf0 R08: 1ffffffff16a3382 R09: fffffbfff16a3383 R10: ffff888051f18e28 R11: ffff888051f18540 R12: 000000000000058e R13: 000000000000058e R14: 0000000000000001 R15: 00000000000c258e FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f585c8f6140 CR3: 0000000097b68000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: __kasan_check_read+0x11/0x20 mm/kasan/common.c:95 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] __lock_acquire+0x1564/0x4a00 kernel/locking/lockdep.c:3924 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] rps_lock net/core/dev.c:221 [inline] process_backlog+0x323/0x780 net/core/dev.c:6153 napi_poll net/core/dev.c:6582 [inline] net_rx_action+0x508/0x1120 net/core/dev.c:6650 __do_softirq+0x262/0x98c kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:337 do_softirq kernel/softirq.c:329 [inline] __local_bh_enable_ip+0x211/0x270 kernel/softirq.c:189 local_bh_enable include/linux/bottom_half.h:32 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:690 [inline] __dev_queue_xmit+0x175c/0x35c0 net/core/dev.c:4090 dev_queue_xmit+0x18/0x20 net/core/dev.c:4096 batadv_send_skb_packet+0x4cc/0x680 net/batman-adv/send.c:108 batadv_send_broadcast_skb+0x25/0x30 net/batman-adv/send.c:127 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:393 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:419 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x69a/0x7c0 net/batman-adv/bat_iv_ogm.c:1706 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352