INFO: task kworker/u4:6:364 blocked for more than 143 seconds. Not tainted 5.5.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:6 D24432 364 2 0x80004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __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 hashlimit_proc_net_exit net/netfilter/xt_hashlimit.c:1267 [inline] hashlimit_net_exit+0x16d/0x3d0 net/netfilter/xt_hashlimit.c:1290 ops_exit_list.isra.0+0xb1/0x160 net/core/net_namespace.c:172 cleanup_net+0x538/0xaf0 net/core/net_namespace.c:597 process_one_work+0x9af/0x1740 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: 4 locks held by kworker/u4:6/364: #0: ffff8880a9a97128 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a9a97128 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a9a97128 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a9a97128 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a9a97128 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880a9a97128 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880a9a97128 ((wq_completion)netns){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc900021b7dc0 (net_cleanup_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff8a4c6388 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0xaf0 net/core/net_namespace.c:559 #3: ffffffff8a550200 (hashlimit_mutex){+.+.}, at: hashlimit_proc_net_exit net/netfilter/xt_hashlimit.c:1267 [inline] #3: ffffffff8a550200 (hashlimit_mutex){+.+.}, at: hashlimit_net_exit+0x16d/0x3d0 net/netfilter/xt_hashlimit.c:1290 1 lock held by khungtaskd/1114: #0: ffffffff899a3f00 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/10575: #0: ffff8880a6ea3de0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/10697: #0: ffff88809701e090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000190b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10698: #0: ffff888097b91090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000198b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10699: #0: ffff8880973a6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000194b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10700: #0: ffff88809865f090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000195b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10701: #0: ffff8880979db090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000196b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10702: #0: ffff8880984fb090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000197b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10703: #0: ffff888094ce5090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900018cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.4/31503: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1114 Comm: khungtaskd Not tainted 5.5.0-rc6-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 31503 Comm: syz-executor.4 Not tainted 5.5.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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:ffffc90001887828 EFLAGS: 00000016 RAX: ffff7fffffffffff RBX: 000000000000082b RCX: ffffffff815a63f2 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8b2f3de0 RBP: ffffc90001887830 R08: 1ffffffff165e7bc R09: fffffbfff165e7bd R10: fffffbfff165e7bc R11: ffffffff8b2f3de7 R12: 0000000000000006 R13: ffff88804c754a98 R14: dffffc0000000000 R15: ffff88804c754a98 FS: 00007f554b1f5700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000400200 CR3: 0000000094266000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __kasan_check_read+0x11/0x20 mm/kasan/common.c:95 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] hlock_class kernel/locking/lockdep.c:163 [inline] mark_lock+0xc2/0x1220 kernel/locking/lockdep.c:3643 mark_held_locks+0xa4/0xf0 kernel/locking/lockdep.c:3360 __trace_hardirqs_on_caller kernel/locking/lockdep.c:3389 [inline] lockdep_hardirqs_on+0x421/0x5e0 kernel/locking/lockdep.c:3434 trace_hardirqs_on+0x67/0x240 kernel/trace/trace_preemptirq.c:31 __local_bh_enable_ip+0x15a/0x270 kernel/softirq.c:194 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_bh+0x2c/0x30 kernel/locking/spinlock.c:207 spin_unlock_bh include/linux/spinlock.h:383 [inline] htable_selective_cleanup+0x219/0x330 net/netfilter/xt_hashlimit.c:387 htable_destroy net/netfilter/xt_hashlimit.c:422 [inline] htable_put+0x176/0x220 net/netfilter/xt_hashlimit.c:449 hashlimit_mt_destroy+0x56/0x70 net/netfilter/xt_hashlimit.c:985 cleanup_match+0xde/0x170 net/ipv6/netfilter/ip6_tables.c:478 cleanup_entry+0xd7/0x270 net/ipv4/netfilter/ip_tables.c:645 do_replace net/ipv4/netfilter/ip_tables.c:1148 [inline] do_ipt_set_ctl+0x3e4/0x4c2 net/ipv4/netfilter/ip_tables.c:1672 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline] ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240 tcp_setsockopt net/ipv4/tcp.c:3158 [inline] tcp_setsockopt+0x8f/0xe0 net/ipv4/tcp.c:3152 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3149 __sys_setsockopt+0x261/0x4c0 net/socket.c:2117 __do_sys_setsockopt net/socket.c:2133 [inline] __se_sys_setsockopt net/socket.c:2130 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2130 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45aff9 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:00007f554b1f4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f554b1f56d4 RCX: 000000000045aff9 RDX: 0000000000000040 RSI: 0004000000000000 RDI: 0000000000000003 RBP: 000000000075bfc8 R08: 00000000000000f0 R09: 0000000000000000 R10: 0000000020000740 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000009c3 R14: 00000000004caefa R15: 000000000075bfd4