INFO: task khugepaged:1085 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 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+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/u4:1/21: #0: ffff8880a7e18d28 ((wq_completion)writeback){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a7e18d28 ((wq_completion)writeback){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a7e18d28 ((wq_completion)writeback){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a7e18d28 ((wq_completion)writeback){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a7e18d28 ((wq_completion)writeback){+.+.}, at: set_work_data kernel/workqueue.c:614 [inline] #0: ffff8880a7e18d28 ((wq_completion)writeback){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:641 [inline] #0: ffff8880a7e18d28 ((wq_completion)writeback){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2234 #1: ffff8880a9a07dc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2238 #2: ffff8882159fc0d8 (&type->s_umount_key#32){++++}, at: trylock_super+0x22/0x110 fs/super.c:418 #3: ffff8882159fe990 (&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: ffff8882159fe990 (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344 1 lock held by rsyslogd/8923: #0: ffff8880a606a3e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9013: #0: ffff888095a85090 (&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/9014: #0: ffff8880a5b2c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f452e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9015: #0: ffff8880a8964090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9016: #0: ffff8880a19fc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f412e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9017: #0: ffff888095a1e090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f3d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9018: #0: ffff8880a3a33090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f492e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9019: #0: ffff8880a7b19090 (&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 1 lock held by syz-executor.3/10309: #0: ffffffff88ff0980 (event_mutex){+.+.}, at: perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:241 3 locks held by syz-executor.1/10318: #0: ffff888060fc76d0 (&sig->cred_guard_mutex){+.+.}, at: __do_sys_perf_event_open+0xe7e/0x2b90 kernel/events/core.c:11060 #1: ffffffff8ab17b08 (&pmus_srcu){....}, at: perf_event_alloc.part.0+0xde2/0x3560 kernel/events/core.c:10602 #2: ffffffff88ff0980 (event_mutex){+.+.}, at: perf_trace_init+0x58/0x250 kernel/trace/trace_event_perf.c:223 1 lock held by syz-executor.1/10324: #0: ffff888060fc76d0 (&sig->cred_guard_mutex){+.+.}, at: __do_sys_perf_event_open+0xe7e/0x2b90 kernel/events/core.c:11060 1 lock held by syz-executor.4/10320: #0: ffffffff89520dc0 (loop_ctl_mutex){+.+.}, at: __loop_clr_fd+0x88/0xd60 drivers/block/loop.c:1093 2 locks held by blkid/10325: #0: ffff888090e57938 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1600 fs/block_dev.c:1553 #1: ffffffff89520dc0 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1784 3 locks held by syz-executor.5/10328: #0: ffff88805ed74550 (&sig->cred_guard_mutex){+.+.}, at: __do_sys_perf_event_open+0xe7e/0x2b90 kernel/events/core.c:11060 #1: ffffffff8ab17b08 (&pmus_srcu){....}, at: perf_event_alloc.part.0+0xde2/0x3560 kernel/events/core.c:10602 #2: ffffffff88ff0980 (event_mutex){+.+.}, at: perf_trace_init+0x58/0x250 kernel/trace/trace_event_perf.c:223 2 locks held by blkid/10329: #0: ffff8880a30ba1b8 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1600 fs/block_dev.c:1553 #1: ffffffff89520dc0 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1784 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1078 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: 10320 Comm: syz-executor.4 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:io_serial_out+0x73/0x90 drivers/tty/serial/8250/8250_port.c:457 Code: 00 49 8d 7c 24 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 19 41 03 5c 24 38 44 89 e8 89 da ee <5b> 41 5c 41 5d 5d c3 e8 f1 75 1c fe eb c0 e8 4a 76 1c fe eb e0 0f RSP: 0018:ffff88805d6f76d8 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: ffffffff8392da46 RDI: ffffffff8b59da98 RBP: ffff88805d6f76f0 R08: ffff888095d2a340 R09: ffffed100badeecd R10: ffffed100badeecc R11: 0000000000000003 R12: ffffffff8b59da60 R13: 0000000000000000 R14: ffffffff8b59daa8 R15: ffff88805d6f77e0 FS: 00007fd7f3ba5700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000738000 CR3: 000000009afe1000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_port_out include/linux/serial_core.h:265 [inline] serial8250_console_write+0x314/0x9a0 drivers/tty/serial/8250/8250_port.c:3152 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:587 call_console_drivers kernel/printk/printk.c:1791 [inline] console_unlock+0xb7a/0xf00 kernel/printk/printk.c:2473 vprintk_emit+0x2a0/0x700 kernel/printk/printk.c:1996 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 kobject_uevent_env+0xe2/0x1023 lib/kobject_uevent.c:476 kobject_uevent+0x20/0x26 lib/kobject_uevent.c:641 __loop_clr_fd+0x4ee/0xd60 drivers/block/loop.c:1136 loop_clr_fd drivers/block/loop.c:1224 [inline] lo_ioctl+0x2bd/0x1460 drivers/block/loop.c:1593 __blkdev_driver_ioctl block/ioctl.c:304 [inline] blkdev_ioctl+0xedb/0x1c20 block/ioctl.c:606 block_ioctl+0xee/0x130 fs/block_dev.c:1954 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a087 Code: 48 83 c4 08 48 89 d8 5b 5d c3 66 0f 1f 84 00 00 00 00 00 48 89 e8 48 f7 d8 48 39 c3 0f 92 c0 eb 92 66 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 0d b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fd7f3ba4a88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd7f3ba4b40 RCX: 000000000045a087 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004 RBP: 0000000000000000 R08: 00007fd7f3ba4b40 R09: 00007fd7f3ba4ae0 R10: 0000000000008401 R11: 0000000000000246 R12: 0000000000000003 R13: 00000000004c9a78 R14: 00000000004e1770 R15: 00000000ffffffff