INFO: task kworker/u4:1:21 blocked for more than 143 seconds. Not tainted 5.4.0-rc1+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:1 D24872 21 2 0x80004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x74b/0xb80 kernel/sched/core.c:4069 schedule+0x131/0x1e0 kernel/sched/core.c:4136 rxrpc_destroy_all_calls+0x16a/0x530 net/rxrpc/call_object.c:631 rxrpc_exit_net+0x61/0xb0 net/rxrpc/net_ns.c:121 ops_exit_list net/core/net_namespace.c:172 [inline] cleanup_net+0x69a/0xaa0 net/core/net_namespace.c:594 process_one_work+0x7ef/0x10e0 kernel/workqueue.c:2269 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 3 locks held by kworker/u4:1/21: #0: ffff88821b6acba8 ((wq_completion)netns){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff88821b6acba8 ((wq_completion)netns){+.+.}, at: process_one_work+0x75d/0x10e0 kernel/workqueue.c:2242 #1: ffff8880a9a2fd78 (net_cleanup_work){+.+.}, at: process_one_work+0x79f/0x10e0 kernel/workqueue.c:2244 #2: ffffffff88b00a68 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa5/0xaa0 net/core/net_namespace.c:556 1 lock held by khungtaskd/1064: #0: ffffffff888d3ec0 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 2 locks held by getty/8036: #0: ffff88808e0d6f50 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8037: #0: ffff8880a76fc250 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f212e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8038: #0: ffff888091192c50 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f312e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8039: #0: ffff8880a76fcad0 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f1d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8040: #0: ffff8880911934d0 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8041: #0: ffff8880a76fd350 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/8042: #0: ffff8880a74f6ad0 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f092e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.5/30048: #0: ffffffff88b00a68 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x32/0x5f0 net/core/dev.c:1644 1 lock held by syz-executor.5/30052: #0: ffffffff88b00a68 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x32/0x5f0 net/core/dev.c:1644 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1064 Comm: khungtaskd Not tainted 5.4.0-rc1+ #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+0x1d8/0x2f8 lib/dump_stack.c:113 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 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+0xbb9/0xbd0 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: 30 Comm: kworker/u4:2 Not tainted 5.4.0-rc1+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:check_memory_region+0x4/0x2e0 mm/kasan/generic.c:191 Code: 88 eb 0c 31 db 48 c7 c7 b4 6b 39 88 4c 89 fe 31 c0 e8 23 fd af ff eb cf 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 <41> 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 fd 01 00 00 48 89 RSP: 0018:ffff8880a9aafa50 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000029 RCX: ffffffff81587ba1 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff895db4e0 RBP: ffff8880a9aafa50 R08: dffffc0000000000 R09: fffffbfff12bb6b2 R10: fffffbfff12bb6b2 R11: 0000000000000000 R12: 67777e0c82d79927 R13: ffff8880a9a9c910 R14: ffffffff892059a0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5bde0e6000 CR3: 00000000a9694000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __kasan_check_read+0x11/0x20 mm/kasan/common.c:92 test_bit include/asm-generic/bitops-instrumented.h:237 [inline] hlock_class kernel/locking/lockdep.c:163 [inline] __lock_acquire+0xbe1/0x1be0 kernel/locking/lockdep.c:3952 lock_acquire+0x158/0x250 kernel/locking/lockdep.c:4487 rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:208 rcu_read_lock include/linux/rcupdate.h:599 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:407 [inline] batadv_nc_worker+0xdc/0x600 net/batman-adv/network-coding.c:718 process_one_work+0x7ef/0x10e0 kernel/workqueue.c:2269 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352