RAX: ffffffffffffffda RBX: 00007f24883aa6d4 RCX: 0000000000455259 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000020000000 R09: 0000000000000010 R10: 0000000020000802 R11: 0000000000000246 R12: 0000000000000014 R13: 00000000000004f7 R14: 00000000006fa7c8 R15: 0000000000000003 INFO: task kworker/0:3:2082 blocked for more than 120 seconds. Not tainted 4.16.0+ #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:3 D24056 2082 2 0x80000000 Workqueue: events cgwb_release_workfn Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x807/0x1e40 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 bit_wait+0x18/0x90 kernel/sched/wait_bit.c:197 __wait_on_bit+0xb3/0x130 kernel/sched/wait_bit.c:48 out_of_line_wait_on_bit+0x204/0x3a0 kernel/sched/wait_bit.c:63 wait_on_bit include/linux/wait_bit.h:76 [inline] wb_shutdown+0x370/0x470 mm/backing-dev.c:377 cgwb_release_workfn+0x87/0x750 mm/backing-dev.c:520 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Showing all locks held in the system: 2 locks held by khungtaskd/883: #0: 000000005be5acfd (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 000000005be5acfd (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 0000000058b95314 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 2 locks held by kworker/0:3/2082: #0: 000000000b3ac204 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 000000000b3ac204 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000b3ac204 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000b3ac204 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 000000000b3ac204 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000b3ac204 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000b3ac204 ((wq_completion)"events"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 0000000001438f07 ((work_completion)(&wb->release_work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 2 locks held by getty/4489: #0: 000000002ae28075 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ef52a5d8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4490: #0: 00000000670767fe (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003c618ab7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4491: #0: 00000000612a06c9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000001d387c3e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4492: #0: 0000000076577d77 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ed124e1a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4493: #0: 000000005f96218b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000620fb6f6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4494: #0: 00000000e62d85e0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000017b11a0c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4495: #0: 00000000bdad71ca (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000409503c6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 883 Comm: khungtaskd Not tainted 4.16.0+ #4 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+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4565 Comm: syz-executor0 Not tainted 4.16.0+ #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:kasan_slab_alloc+0xd/0x20 mm/kasan/kasan.c:488 RSP: 0018:ffff880195036be0 EFLAGS: 00000206 RAX: 0000000000000038 RBX: 00000000014000c0 RCX: 00000000014000c0 RDX: 0000000000000038 RSI: ffff8801cbc6e0b0 RDI: ffff8801dac10040 RBP: ffff880195036be0 R08: ffff8801ae6aad78 R09: 0000000000000006 R10: ffff8801ae6aa500 R11: 0000000000000000 R12: ffff8801cbc6e0b0 R13: ffff8801dac10040 R14: ffff8801dac10040 R15: 00000000014000c0 FS: 00000000020b2940(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000093002d CR3: 0000000195602000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: slab_post_alloc_hook mm/slab.h:443 [inline] slab_alloc mm/slab.c:3380 [inline] kmem_cache_alloc+0x11b/0x760 mm/slab.c:3540 ptlock_alloc+0x20/0x80 mm/memory.c:4729 ptlock_init include/linux/mm.h:1803 [inline] pgtable_page_ctor include/linux/mm.h:1837 [inline] pte_alloc_one+0x6b/0x120 arch/x86/mm/pgtable.c:32 __pte_alloc+0x2a/0x340 mm/memory.c:654 copy_pte_range mm/memory.c:1076 [inline] copy_pmd_range mm/memory.c:1152 [inline] copy_pud_range mm/memory.c:1186 [inline] copy_p4d_range mm/memory.c:1208 [inline] copy_page_range+0x1655/0x24b0 mm/memory.c:1270 dup_mmap kernel/fork.c:513 [inline] dup_mm kernel/fork.c:1233 [inline] copy_mm kernel/fork.c:1287 [inline] copy_process.part.39+0x4be2/0x6ee0 kernel/fork.c:1793 copy_process kernel/fork.c:1606 [inline] _do_fork+0x291/0x12a0 kernel/fork.c:2087 SYSC_clone kernel/fork.c:2194 [inline] SyS_clone+0x37/0x50 kernel/fork.c:2188 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45390a RSP: 002b:00007fff92376b20 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fff92376b20 RCX: 000000000045390a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fff92376b60 R08: 0000000000000001 R09: 00000000020b2940 R10: 00000000020b2c10 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000001380 Code: 00 00 48 01 f7 31 f6 48 89 e5 e8 3f bc 95 05 5d c3 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 63 47 74 89 d1 48 89 c2 48 89 e5 7e f9 ff ff 5d c3 66 90 66 2e 0f 1f 84 00 00 00 00 00 55 b9 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.040 msecs