INFO: task syz-executor.4:14608 blocked for more than 143 seconds. Not tainted 5.4.0-rc7+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D24040 14608 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x909/0x1ee0 kernel/sched/core.c:4078 schedule+0xd9/0x260 kernel/sched/core.c:4145 exp_funnel_lock kernel/rcu/tree_exp.h:308 [inline] synchronize_rcu_expedited+0x57f/0x5f0 kernel/rcu/tree_exp.h:817 namespace_unlock+0x1d3/0x560 fs/namespace.c:1375 do_umount fs/namespace.c:1598 [inline] ksys_umount+0x739/0xf00 fs/namespace.c:1698 __do_sys_umount fs/namespace.c:1709 [inline] __se_sys_umount fs/namespace.c:1707 [inline] __x64_sys_umount+0x54/0x80 fs/namespace.c:1707 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d067 Code: c5 fe 7f 44 1f 80 c5 f8 77 c3 88 07 88 44 1f ff c3 c3 66 89 07 66 89 44 1f fe c3 89 07 89 44 1f fc c3 48 89 07 c3 48 89 07 48 <89> 44 1f f8 c3 f3 0f 7f 07 f3 0f 7f 44 1f f0 c3 f3 0f 7f 07 f3 0f RSP: 002b:00007ffed5f378a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 00000000000e9679 RCX: 000000000045d067 RDX: 0000000000403a60 RSI: 0000000000000002 RDI: 00007ffed5f37950 RBP: 00000000000035fd R08: 0000000000000000 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000202 R12: 00007ffed5f389e0 R13: 000000000262a940 R14: 0000000000000000 R15: 00007ffed5f389e0 INFO: task syz-executor.3:14706 blocked for more than 143 seconds. Not tainted 5.4.0-rc7+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D24040 14706 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x909/0x1ee0 kernel/sched/core.c:4078 schedule+0xd9/0x260 kernel/sched/core.c:4145 exp_funnel_lock kernel/rcu/tree_exp.h:308 [inline] synchronize_rcu_expedited+0x57f/0x5f0 kernel/rcu/tree_exp.h:817 namespace_unlock+0x1d3/0x560 fs/namespace.c:1375 do_umount fs/namespace.c:1598 [inline] ksys_umount+0x739/0xf00 fs/namespace.c:1698 __do_sys_umount fs/namespace.c:1709 [inline] __se_sys_umount fs/namespace.c:1707 [inline] __x64_sys_umount+0x54/0x80 fs/namespace.c:1707 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d067 Code: c5 fe 7f 44 1f 80 c5 f8 77 c3 88 07 88 44 1f ff c3 c3 66 89 07 66 89 44 1f fe c3 89 07 89 44 1f fc c3 48 89 07 c3 48 89 07 48 <89> 44 1f f8 c3 f3 0f 7f 07 f3 0f 7f 44 1f f0 c3 f3 0f 7f 07 f3 0f RSP: 002b:00007ffc49079328 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 00000000000e95fb RCX: 000000000045d067 RDX: 0000000000403a60 RSI: 0000000000000002 RDI: 00007ffc490793d0 RBP: 0000000000000a18 R08: 0000000000000000 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000206 R12: 00007ffc4907a460 R13: 00000000021a4940 R14: 0000000000000000 R15: 00007ffc4907a460 Showing all locks held in the system: 1 lock held by khungtaskd/1072: #0: ffffffff88fab980 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5337 1 lock held by rsyslogd/8588: #0: ffff8880a57a33a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8678: #0: ffff8880a16db090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f2d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8679: #0: ffff88809c156090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f3b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8680: #0: ffff8880a12e4090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f432e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8681: #0: ffff8880a739a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f372e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8682: #0: ffff88809fc3c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f292e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8683: #0: ffff888095792090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f3f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8684: #0: ffff88809f90a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f112e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:12/13774: #0: ffff8880ae934d18 (&rq->lock){-.-.}, at: newidle_balance+0xa32/0xe90 kernel/sched/fair.c:9834 #1: ffffffff88fab980 (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:5833 #2: ffff8880ae924c18 (&base->lock){-.-.}, at: lock_timer_base+0x56/0x1b0 kernel/time/timer.c:936 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1072 Comm: khungtaskd Not tainted 5.4.0-rc7+ #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+0x9d0/0xef0 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 13774 Comm: kworker/u4:12 Not tainted 5.4.0-rc7+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:trace_softirqs_off+0x135/0x360 kernel/locking/lockdep.c:3530 Code: be 00 00 00 48 8d bb 68 08 00 00 48 b8 00 00 00 00 00 fc ff df c7 83 80 08 00 00 00 00 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 e4 01 00 00 48 8d bb 44 08 00 00 4c 89 a3 68 08 00 00 48 b8 RSP: 0018:ffff8880686e7bf8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff888067efa180 RCX: 0000000000000001 RDX: 1ffff1100cfdf53d RSI: 0000000000000201 RDI: ffff888067efa9e8 RBP: ffff8880686e7c10 R08: 0000000000000000 R09: 0000000000000001 R10: fffffbfff14f014a R11: ffffffff8a780a57 R12: ffffffff8733b698 R13: ffff888067efa180 R14: ffffffff8733c2f0 R15: 0000000000000015 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 0000000092944000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __local_bh_disable_ip+0xf7/0x1b0 kernel/softirq.c:129 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:134 [inline] _raw_spin_lock_bh+0x17/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] batadv_nc_purge_paths+0xd8/0x370 net/batman-adv/network-coding.c:441 batadv_nc_worker+0x2cf/0x760 net/batman-adv/network-coding.c:721 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352