INFO: task khugepaged:950 blocked for more than 143 seconds. Not tainted 5.4.0-rc5-next-20191031 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. khugepaged D27840 950 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x94a/0x1e70 kernel/sched/core.c:4070 schedule+0xdc/0x2b0 kernel/sched/core.c:4144 io_schedule+0x1c/0x70 kernel/sched/core.c:5788 wait_on_page_bit_common mm/filemap.c:1175 [inline] __lock_page+0x422/0xab0 mm/filemap.c:1383 lock_page include/linux/pagemap.h:480 [inline] mpage_prepare_extent_to_map+0xb3f/0xf90 fs/ext4/inode.c:2668 ext4_writepages+0x954/0x2e70 fs/ext4/inode.c:2822 ? 0xffffffff81000000 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 __filemap_fdatawrite_range+0x2bc/0x3b0 mm/filemap.c:421 __filemap_fdatawrite mm/filemap.c:429 [inline] filemap_flush+0x24/0x30 mm/filemap.c:456 collapse_file+0x36b1/0x41a0 mm/khugepaged.c:1652 khugepaged_scan_file mm/khugepaged.c:1890 [inline] khugepaged_scan_mm_slot mm/khugepaged.c:1988 [inline] khugepaged_do_scan mm/khugepaged.c:2072 [inline] khugepaged+0x2da9/0x4360 mm/khugepaged.c:2117 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/u4:3/114: #0: ffff8880a8bb7928 ((wq_completion)writeback){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a8bb7928 ((wq_completion)writeback){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a8bb7928 ((wq_completion)writeback){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a8bb7928 ((wq_completion)writeback){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a8bb7928 ((wq_completion)writeback){+.+.}, at: set_work_data kernel/workqueue.c:614 [inline] #0: ffff8880a8bb7928 ((wq_completion)writeback){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:641 [inline] #0: ffff8880a8bb7928 ((wq_completion)writeback){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2234 #1: ffff8880a952fdc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2238 #2: ffff888215e160d8 (&type->s_umount_key#32){++++}, at: trylock_super+0x22/0x110 fs/super.c:418 #3: ffff888215e18990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 1 lock held by khungtaskd/943: #0: ffffffff88faba40 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5336 3 locks held by kworker/u4:5/946: #0: ffff88821b6bd928 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff88821b6bd928 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88821b6bd928 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff88821b6bd928 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff88821b6bd928 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:614 [inline] #0: ffff88821b6bd928 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:641 [inline] #0: ffff88821b6bd928 ((wq_completion)netns){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2234 #1: ffff8880a88f7dc0 (net_cleanup_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2238 #2: ffffffff899ace48 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0xaf0 net/core/net_namespace.c:559 1 lock held by khugepaged/950: #0: ffff888215e18990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 1 lock held by rsyslogd/8815: 2 locks held by getty/8905: #0: ffff8880a83b5090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f092e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8906: #0: ffff888097517090 (&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+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8907: #0: ffff88809873d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f1d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8908: #0: ffff8880a0be1090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f252e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8909: #0: ffff8880a7338090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f012e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8910: #0: ffff888095cf9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f212e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8911: #0: ffff88809c560090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005ef12e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 943 Comm: khungtaskd Not tainted 5.4.0-rc5-next-20191031 #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+0x172/0x1f0 lib/dump_stack.c:113 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:269 [inline] watchdog+0xc8f/0x1350 kernel/hung_task.c:353 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: 9747 Comm: syz-executor.1 Not tainted 5.4.0-rc5-next-20191031 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:2861 [inline] RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:2881 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:2936 [inline] RIP: 0010:__lock_acquire+0x1748/0x4a00 kernel/locking/lockdep.c:3955 Code: ff ff 49 c1 e8 31 4a 8d 04 c5 00 29 75 8a 48 89 c2 48 89 85 70 ff ff ff 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 85 5c 2d 00 00 4a 8b 1c c5 00 29 75 8a 48 85 db 74 61 48 83 eb RSP: 0018:ffff8880ae809b28 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81594562 RDX: 1ffffffff14ebe04 RSI: 0000000000000008 RDI: ffffffff8a79e9a0 RBP: ffff8880ae809c40 R08: 00000000000018e4 R09: fffffbfff14f3d35 R10: ffff88808f7aab98 R11: ffff88808f7aa280 R12: 00000000e77d9366 R13: ffffffff89c86db0 R14: ffff88808f7aab70 R15: 0000000000000000 FS: 00000000029fa940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000a71da0 CR3: 00000000a7c66000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4487 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 debug_object_deactivate lib/debugobjects.c:706 [inline] debug_object_deactivate+0x104/0x320 lib/debugobjects.c:694 debug_timer_deactivate kernel/time/timer.c:719 [inline] debug_deactivate kernel/time/timer.c:768 [inline] detach_timer kernel/time/timer.c:813 [inline] expire_timers kernel/time/timer.c:1438 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0x520/0x1790 kernel/time/timer.c:1786 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline] RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1751 [inline] RIP: 0010:vprintk_emit+0x5da/0x700 kernel/printk/printk.c:1995 Code: 00 48 b8 00 00 00 00 00 fc ff df 41 80 3c 06 00 0f 85 f8 00 00 00 48 83 3d a2 3d 96 07 00 74 6a e8 4b 81 16 00 48 89 df 57 9d <0f> 1f 44 00 00 e9 06 ff ff ff e8 37 81 16 00 49 c1 ee 03 e8 7e 01 RSP: 0018:ffff88805cb37790 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff88808f7aa280 RBX: 0000000000000293 RCX: 0000000000000006 RDX: 0000000000000000 RSI: ffffffff815ce445 RDI: 0000000000000293 RBP: ffff88805cb377d8 R08: 1ffffffff14f3d37 R09: fffffbfff14f3d38 R10: fffffbfff14f3d37 R11: ffffffff8a79e9bf R12: 0000000000000052 R13: 0000000000000200 R14: 1ffffffff11e643c R15: ffff8880a89e0540 vprintk_default+0x28/0x30 kernel/printk/printk.c:2023 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386 printk+0xba/0xed kernel/printk/printk.c:2056 fill_kobj_path lib/kobject.c:160 [inline] kobject_get_path.cold+0x38/0x47 lib/kobject.c:182 kobject_uevent_env+0x3ab/0x1023 lib/kobject_uevent.c:528 kobject_uevent+0x20/0x26 lib/kobject_uevent.c:641 device_add+0xac4/0x1de0 drivers/base/core.c:2343 netdev_register_kobject+0x183/0x3b0 net/core/net-sysfs.c:1746 register_netdevice+0x999/0x1020 net/core/dev.c:9315 register_netdev+0x30/0x50 net/core/dev.c:9437 loopback_net_init+0x7a/0x160 drivers/net/loopback.c:214 ops_init+0xb3/0x420 net/core/net_namespace.c:137 setup_net+0x2d5/0x8b0 net/core/net_namespace.c:335 copy_net_ns+0x29e/0x520 net/core/net_namespace.c:476 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:103 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:202 ksys_unshare+0x444/0x980 kernel/fork.c:2889 __do_sys_unshare kernel/fork.c:2957 [inline] __se_sys_unshare kernel/fork.c:2955 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2955 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45cce7 Code: 00 00 00 b8 63 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 cd 8b fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 ad 8b fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc2dd339b8 EFLAGS: 00000202 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 000000000075ca28 RCX: 000000000045cce7 RDX: 0000000000000000 RSI: 00007ffc2dd33960 RDI: 0000000040000000 RBP: 00000000000000f8 R08: 0000000000000000 R09: 0000000000000005 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000415d20 R13: 00007ffc2dd33c28 R14: 0000000000000000 R15: 0000000000000000