INFO: task syz-executor5:8137 blocked for more than 120 seconds. Not tainted 4.15.0-rc2+ #213 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D24272 8137 3394 0x00000004 Call Trace: context_switch kernel/sched/core.c:2799 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3375 schedule+0xf5/0x430 kernel/sched/core.c:3434 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3492 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x1759/0x1e00 block/ioctl.c:601 block_ioctl+0xea/0x130 fs/block_dev.c:1860 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x1f/0x96 RIP: 0033:0x452a39 RSP: 002b:00007fd423a08c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452a39 RDX: 000000002078ef18 RSI: 0000000000004c04 RDI: 0000000000000017 RBP: 0000000000000061 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee9b8 R13: 00000000ffffffff R14: 00007fd423a096d4 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/674: #0: (rcu_read_lock){....}, at: [<000000003b414fba>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000003b414fba>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000090e98f51>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554 1 lock held by rsyslogd/2996: #0: (&f->f_pos_lock){+.+.}, at: [<000000008633564a>] spin_lock include/linux/spinlock.h:315 [inline] #0: (&f->f_pos_lock){+.+.}, at: [<000000008633564a>] double_lock_hb kernel/futex.c:1512 [inline] #0: (&f->f_pos_lock){+.+.}, at: [<000000008633564a>] futex_wake_op kernel/futex.c:1654 [inline] #0: (&f->f_pos_lock){+.+.}, at: [<000000008633564a>] do_futex+0x108e/0x2280 kernel/futex.c:3501 2 locks held by getty/3118: #0: (&tty->ldisc_sem){++++}, at: [<00000000c06e7bcd>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000056805d2>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3119: #0: (&tty->ldisc_sem){++++}, at: [<00000000c06e7bcd>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000056805d2>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3120: #0: (&tty->ldisc_sem){++++}, at: [<00000000c06e7bcd>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000056805d2>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3121: #0: (&tty->ldisc_sem){++++}, at: [<00000000c06e7bcd>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000056805d2>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3122: #0: (&tty->ldisc_sem){++++}, at: [<00000000c06e7bcd>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000056805d2>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3123: #0: (&tty->ldisc_sem){++++}, at: [<00000000c06e7bcd>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000056805d2>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3124: #0: (&tty->ldisc_sem){++++}, at: [<00000000c06e7bcd>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000056805d2>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 1 lock held by syz-executor5/8137: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d63e3fea>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor5/8152: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d63e3fea>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor2/8140: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d63e3fea>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor2/8149: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d63e3fea>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor2/8154: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d63e3fea>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor2/8164: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d63e3fea>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by blkid/8150: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d63e3fea>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 674 Comm: khungtaskd Not tainted 4.15.0-rc2+ #213 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 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:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x37a/0x440 kernel/kthread.c:238 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:441 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc2+ #213 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:update_cpu_capacity kernel/sched/fair.c:7577 [inline] RIP: 0010:update_group_capacity+0x55e/0xe90 kernel/sched/fair.c:7602 RSP: 0018:ffff8801db406e98 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 1ffff1003b680dd9 RCX: ffff8801da2a7980 RDX: dffffc0000000000 RSI: 000000000000024d RDI: ffff8801da2a80c8 RBP: ffff8801db406fd0 R08: ffff8801da2a7900 R09: 1ffff1003b454f23 R10: ffff8801da2a80d8 R11: 0000000000000000 R12: ffff8801db406fa8 R13: 0000000000025a80 R14: 0000000000000000 R15: ffff8801da2a8090 FS: 0000000000000000(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c4454cded0 CR3: 00000001cc2e9000 CR4: 00000000001406f0 DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: update_sd_lb_stats+0x365/0x2350 kernel/sched/fair.c:7965 find_busiest_group+0xf9/0x1c60 kernel/sched/fair.c:8230 load_balance+0x639/0x34c0 kernel/sched/fair.c:8495 rebalance_domains+0x786/0xcc0 kernel/sched/fair.c:9161 run_rebalance_domains+0x381/0x780 kernel/sched/fair.c:9383 __do_softirq+0x29d/0xbb2 kernel/softirq.c:285 invoke_softirq kernel/softirq.c:365 [inline] irq_exit+0x1d3/0x210 kernel/softirq.c:405 scheduler_ipi+0x32a/0x830 kernel/sched/core.c:1803 smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:819 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffffffff85e07d08 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffffffff0bc0fa4 RCX: 0000000000000000 RDX: 1ffffffff0bd9734 RSI: 0000000000000001 RDI: ffffffff85ecb9a0 RBP: ffffffff85e07d08 R08: ffffffff85beaae0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff85e07dc0 R14: ffffffff865eb0a0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x460 arch/x86/kernel/process.c:348 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:339 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x24a/0x3b0 kernel/sched/idle.c:246 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:351 rest_init+0xed/0xf0 init/main.c:435 start_kernel+0x729/0x74f init/main.c:710 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: df 48 c1 ea 03 80 3c 02 00 0f 85 25 09 00 00 49 8b 4e 10 4c 63 b5 f0 fe ff ff 49 c7 c5 80 5a 02 00 48 ba 00 00 00 00 00 fc ff df <4c> 89 e8 4e 8d 04 f5 e0 aa be 85 4c 89 c7 48 c1 ef 03 80 3c 17