INFO: task khugepaged:1160 blocked for more than 143 seconds. Not tainted 5.8.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. khugepaged D28576 1160 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3458 [inline] __schedule+0x91f/0x2250 kernel/sched/core.c:4215 schedule+0xd0/0x2a0 kernel/sched/core.c:4290 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1884 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x163/0x260 kernel/sched/completion.c:138 __flush_work+0x51f/0xab0 kernel/workqueue.c:3046 lru_add_drain_all+0x3ca/0x590 mm/swap.c:807 khugepaged_do_scan mm/khugepaged.c:2177 [inline] khugepaged+0x10b/0x5a10 mm/khugepaged.c:2238 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Showing all locks held in the system: 5 locks held by kworker/0:0/5: 1 lock held by khungtaskd/1152: #0: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by khugepaged/1160: #0: ffffffff89c44fe8 (lock#4){+.+.}-{3:3}, at: lru_add_drain_all+0x59/0x590 mm/swap.c:778 1 lock held by in:imklog/6682: #0: ffff8880957658f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by agetty/6748: #0: ffff888096db1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90000f442e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by kworker/1:5/14081: #0: ffff8880aa036538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa036538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880aa036538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880aa036538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880aa036538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880aa036538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc900083afda8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 3 locks held by kworker/1:4/27328: #0: ffff88809a001d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88809a001d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88809a001d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88809a001d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff88809a001d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff88809a001d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90003d67da8 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xa3/0x1280 net/ipv6/addrconf.c:4002 1 lock held by syz-executor.0/10534: #0: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x705/0xac0 net/core/dev.c:9791 2 locks held by syz-executor.4/10572: #0: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8a7b8b28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5457 #1: ffffffff89bc5820 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff89bc5820 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4e8/0x5f0 kernel/rcu/tree_exp.h:838 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1152 Comm: khungtaskd Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.8.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events ipvlan_process_multicast RIP: 0010:nf_hook_slow+0x43/0x1e0 net/netfilter/core.c:511 Code: e8 92 cb 05 fb 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 01 0f 8e 60 01 00 00 44 0f b7 23 <89> ef 44 89 e6 e8 63 c7 05 fb 44 39 e5 0f 83 0c 01 00 00 49 bf 00 RSP: 0018:ffffc90000007bc8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888097cabf00 RCX: 0000000000000000 RDX: 1ffff11012f957e0 RSI: ffffffff866df0fe RDI: ffff8880362af640 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff8c59aa27 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000006 R13: ffff8880362af640 R14: ffffc90000007c58 R15: ffff888097cabf00 FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc3dc2edc0 CR3: 0000000009a79000 CR4: 00000000001406f0 DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: nf_hook.constprop.0+0x35b/0x5d0 include/linux/netfilter.h:262 NF_HOOK include/linux/netfilter.h:305 [inline] ipv6_rcv+0x9e/0x3c0 net/ipv6/ip6_input.c:307 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5281 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5395 process_backlog+0x28d/0x7f0 net/core/dev.c:6239 napi_poll net/core/dev.c:6684 [inline] net_rx_action+0x4a1/0xe60 net/core/dev.c:6752 __do_softirq+0x34c/0xa60 kernel/softirq.c:292 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x111/0x170 arch/x86/kernel/irq_64.c:77 do_softirq kernel/softirq.c:337 [inline] do_softirq+0x16b/0x1e0 kernel/softirq.c:324 __local_bh_enable_ip+0x1f8/0x250 kernel/softirq.c:189 local_bh_enable include/linux/bottom_half.h:32 [inline] ipvlan_process_multicast+0x829/0xd50 drivers/net/ipvlan/ipvlan_core.c:279 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293