INFO: task syz-executor3:21044 blocked for more than 140 seconds. Not tainted 4.14.68+ #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D29272 21044 1848 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_timeout+0x710/0xe60 kernel/time/timer.c:1718 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x3bc/0x4e0 kernel/sched/completion.c:123 flush_work+0x3b8/0x6e0 kernel/workqueue.c:2885 lru_add_drain_all_cpuslocked+0x2ef/0x450 mm/swap.c:722 lru_add_drain_all+0xf/0x20 mm/swap.c:730 SYSC_mlockall mm/mlock.c:802 [inline] SyS_mlockall+0x1d6/0x510 mm/mlock.c:790 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457099 RSP: 002b:00007f56946cfc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000097 RAX: ffffffffffffffda RBX: 00007f56946d06d4 RCX: 0000000000457099 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3150 R14: 00000000004c8158 R15: 0000000000000000 INFO: task syz-executor3:21049 blocked for more than 140 seconds. Not tainted 4.14.68+ #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D28960 21049 1848 0x00000004 Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893 lru_add_drain_all_cpuslocked+0x7f/0x450 mm/swap.c:704 lru_add_drain_all+0xf/0x20 mm/swap.c:730 SYSC_mlockall mm/mlock.c:802 [inline] SyS_mlockall+0x1d6/0x510 mm/mlock.c:790 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457099 RSP: 002b:00007f56946aec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000097 RAX: ffffffffffffffda RBX: 00007f56946af6d4 RCX: 0000000000457099 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3150 R14: 00000000004c8158 R15: 0000000000000001 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x74/0x20f kernel/locking/lockdep.c:4541 2 locks held by getty/1757: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor3/21044: #0: (cpu_hotplug_lock.rw_sem){++++}, at: [] get_online_cpus include/linux/cpu.h:138 [inline] #0: (cpu_hotplug_lock.rw_sem){++++}, at: [] lru_add_drain_all+0xa/0x20 mm/swap.c:729 #1: (lock#4){+.+.}, at: [] lru_add_drain_all_cpuslocked+0x7f/0x450 mm/swap.c:704 2 locks held by syz-executor3/21049: #0: (cpu_hotplug_lock.rw_sem){++++}, at: [] get_online_cpus include/linux/cpu.h:138 [inline] #0: (cpu_hotplug_lock.rw_sem){++++}, at: [] lru_add_drain_all+0xa/0x20 mm/swap.c:729 #1: (lock#4){+.+.}, at: [] lru_add_drain_all_cpuslocked+0x7f/0x450 mm/swap.c:704 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.68+ #4 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 nmi_cpu_backtrace.cold.0+0x47/0x85 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x121/0x146 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x574/0xa70 kernel/hung_task.c:252 kthread+0x348/0x420 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 20943 Comm: syz-executor1 Not tainted 4.14.68+ #4 task: ffff88019f4b8000 task.stack: ffff88019f640000 RIP: 0033:0x4023cb RSP: 002b:00007f0954064690 EFLAGS: 00000282 RAX: 00000000c1f5618a RBX: 000000000000000b RCX: 0000000000457099 RDX: 0000000000457099 RSI: 00007f09540646c0 RDI: 000000000000000b RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d45c0 R14: 00000000004c88b1 R15: 0000000000000000 FS: 00007f0954065700(0000) GS:ffff8801dbb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000018b582002 CR4: 00000000001606a0 DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600