INFO: task khugepaged:1085 blocked for more than 143 seconds. Not tainted 5.4.0-rc5-next-20191030 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. khugepaged D27840 1085 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+0xb6a/0x2e70 fs/ext4/inode.c:2866 ? 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/u4:2/24: #0: ffff8880a786d928 ((wq_completion)writeback){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a786d928 ((wq_completion)writeback){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a786d928 ((wq_completion)writeback){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a786d928 ((wq_completion)writeback){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a786d928 ((wq_completion)writeback){+.+.}, at: set_work_data kernel/workqueue.c:614 [inline] #0: ffff8880a786d928 ((wq_completion)writeback){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:641 [inline] #0: ffff8880a786d928 ((wq_completion)writeback){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2234 #1: ffff8880a9a87dc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2238 #2: ffff88809b0c40d8 (&type->s_umount_key#32){++++}, at: trylock_super+0x22/0x110 fs/super.c:418 #3: ffff88809b0c6990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 1 lock held by khungtaskd/1078: #0: ffffffff88faba40 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5336 1 lock held by khugepaged/1085: #0: ffff88809b0c6990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 1 lock held by rsyslogd/8613: #0: ffff88809aa5f360 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8703: #0: ffff8880979e7090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8704: #0: ffff8880984cf090 (&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/8705: #0: ffff888099c8f090 (&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/8706: #0: ffff88809ad8c090 (&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/8707: #0: ffff888099ff1090 (&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/8708: #0: ffff8880a8398090 (&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+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8709: #0: ffff888092bb1090 (&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 1 lock held by syz-execprog/8732: #0: ffff8880a65ff368 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7e/0xb2 fs/ext4/inode.c:6291 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1078 Comm: khungtaskd Not tainted 5.4.0-rc5-next-20191030 #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: 0 Comm: swapper/0 Not tainted 5.4.0-rc5-next-20191030 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:arch_cpu_idle_enter+0x0/0x20 arch/x86/kernel/process.c:556 Code: e8 a5 49 85 00 48 8b 74 24 20 e9 f3 f1 ff ff 4c 89 ff e8 93 49 85 00 e9 16 f0 ff ff 4c 89 ff e8 86 49 85 00 e9 e2 ef ff ff 90 <55> 31 ff 48 89 e5 e8 15 0c 06 00 e8 30 cd fe ff 5d c3 0f 1f 40 00 RSP: 0018:ffffffff88e07d48 EFLAGS: 00000047 RAX: 0000000000000001 RBX: ffffffff88e7a1c0 RCX: ffffffff81517c07 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff89c80640 RBP: ffffffff88e07e10 R08: 1ffffffff13900c8 R09: fffffbfff13900c9 R10: fffffbfff13900c8 R11: ffffffff89c80647 R12: dffffc0000000000 R13: ffffffff89c80640 R14: ffffffff88e7a1c0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000000a390a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x904/0x943 init/main.c:784 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242