INFO: task khugepaged:766 blocked for more than 120 seconds. Not tainted 4.15.0-rc9+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. khugepaged D22624 766 2 0x80000000 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 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline] rwsem_down_read_failed+0x401/0x6e0 kernel/locking/rwsem-xadd.c:286 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0xa4/0x150 kernel/locking/rwsem.c:26 khugepaged_scan_mm_slot mm/khugepaged.c:1677 [inline] khugepaged_do_scan mm/khugepaged.c:1810 [inline] khugepaged+0x9d8/0x1400 mm/khugepaged.c:1855 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541 Showing all locks held in the system: 2 locks held by khungtaskd/760: #0: (rcu_read_lock){....}, at: [<000000006bc8130a>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000006bc8130a>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000c3f83f85>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4464 1 lock held by khugepaged/766: #0: (&mm->mmap_sem){++++}, at: [<000000007e2cf91e>] khugepaged_scan_mm_slot mm/khugepaged.c:1677 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000007e2cf91e>] khugepaged_do_scan mm/khugepaged.c:1810 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000007e2cf91e>] khugepaged+0x9d8/0x1400 mm/khugepaged.c:1855 1 lock held by rsyslogd/3992: #0: (&f->f_pos_lock){+.+.}, at: [<000000004eb02fa5>] spin_lock include/linux/spinlock.h:310 [inline] #0: (&f->f_pos_lock){+.+.}, at: [<000000004eb02fa5>] double_lock_hb kernel/futex.c:1512 [inline] #0: (&f->f_pos_lock){+.+.}, at: [<000000004eb02fa5>] futex_wake_op kernel/futex.c:1654 [inline] #0: (&f->f_pos_lock){+.+.}, at: [<000000004eb02fa5>] do_futex+0x13bf/0x22a0 kernel/futex.c:3555 2 locks held by getty/4114: #0: (&tty->ldisc_sem){++++}, at: [<000000000eab988b>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bccd9c60>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4115: #0: (&tty->ldisc_sem){++++}, at: [<000000000eab988b>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bccd9c60>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4116: #0: (&tty->ldisc_sem){++++}, at: [<000000000eab988b>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bccd9c60>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4117: #0: (&tty->ldisc_sem){++++}, at: [<000000000eab988b>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bccd9c60>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4118: #0: (&tty->ldisc_sem){++++}, at: [<000000000eab988b>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bccd9c60>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4119: #0: (&tty->ldisc_sem){++++}, at: [<000000000eab988b>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bccd9c60>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4120: #0: (&tty->ldisc_sem){++++}, at: [<000000000eab988b>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bccd9c60>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor3/26900: #0: (&mm->mmap_sem){++++}, at: [<000000008ed81e9c>] exit_mm kernel/exit.c:510 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000008ed81e9c>] do_exit+0x4b0/0x1ad0 kernel/exit.c:852 1 lock held by syz-executor3/26908: #0: (&mm->mmap_sem){++++}, at: [<000000008ed81e9c>] exit_mm kernel/exit.c:510 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000008ed81e9c>] do_exit+0x4b0/0x1ad0 kernel/exit.c:852 1 lock held by syz-executor3/26919: #0: (&mm->mmap_sem){++++}, at: [<000000008ed81e9c>] exit_mm kernel/exit.c:510 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000008ed81e9c>] do_exit+0x4b0/0x1ad0 kernel/exit.c:852 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 760 Comm: khungtaskd Not tainted 4.15.0-rc9+ #9 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+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 26923 Comm: syz-executor3 Not tainted 4.15.0-rc9+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__mutex_lock+0x5fc/0x1a80 kernel/locking/mutex.c:892 RSP: 0018:ffff8801ab0d73e0 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffff8801cd15b890 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffed003561aef0 RBP: ffff8801ab0d77c0 R08: ffffffff81875792 R09: 0000000000000004 R10: ffff8801ab0d72b0 R11: 0000000000000005 R12: 0000000000000000 R13: dffffc0000000000 R14: ffffffff88142200 R15: fffffbfff1028440 FS: 00007fe979ca0700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000041b9e0 CR3: 00000001b9d21005 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_mmap+0x6b2/0x1b70 kernel/events/core.c:5280 call_mmap include/linux/fs.h:1777 [inline] mmap_region+0xa99/0x15a0 mm/mmap.c:1705 do_mmap+0x6c0/0xe00 mm/mmap.c:1483 do_mmap_pgoff include/linux/mm.h:2217 [inline] vm_mmap_pgoff+0x1de/0x280 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1533 [inline] SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1491 SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007fe979c9fc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fe979ca0700 RCX: 0000000000453299 RDX: 0000000000000000 RSI: 0000000000002000 RDI: 0000000020006000 RBP: 00007fffca4fb2d0 R08: 0000000000000014 R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000212 R12: 0000000000000000 R13: 00007fffca4fb24f R14: 00007fe979ca09c0 R15: 000000000000000a Code: 03 8d 80 fc ff ff 31 c0 48 8d 79 08 48 c7 01 00 00 00 00 48 c7 41 60 00 00 00 00 48 83 e7 f8 48 29 f9 83 c1 68 c1 e9 03 f3 48 ab <48> 8d 65 d0 89 d0 5b 41 5a 41 5c 41 5d 41 5e 41 5f 5d 49 8d 62