INFO: task khugepaged:767 blocked for more than 120 seconds. Not tainted 4.15.0+ #10 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. khugepaged D22864 767 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2845 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3421 schedule+0xf5/0x430 kernel/sched/core.c:3480 __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:542 Showing all locks held in the system: 2 locks held by khungtaskd/761: #0: (rcu_read_lock){....}, at: [<00000000130323c1>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000130323c1>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000b71cc8f4>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by khugepaged/767: #0: (&mm->mmap_sem){++++}, at: [<00000000094b5162>] khugepaged_scan_mm_slot mm/khugepaged.c:1677 [inline] #0: (&mm->mmap_sem){++++}, at: [<00000000094b5162>] khugepaged_do_scan mm/khugepaged.c:1810 [inline] #0: (&mm->mmap_sem){++++}, at: [<00000000094b5162>] khugepaged+0x9d8/0x1400 mm/khugepaged.c:1855 2 locks held by getty/4076: #0: (&tty->ldisc_sem){++++}, at: [<00000000e7e1c8ff>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000af6756ad>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4077: #0: (&tty->ldisc_sem){++++}, at: [<00000000e7e1c8ff>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000af6756ad>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4078: #0: (&tty->ldisc_sem){++++}, at: [<00000000e7e1c8ff>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000af6756ad>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4079: #0: (&tty->ldisc_sem){++++}, at: [<00000000e7e1c8ff>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000af6756ad>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4080: #0: (&tty->ldisc_sem){++++}, at: [<00000000e7e1c8ff>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000af6756ad>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4081: #0: (&tty->ldisc_sem){++++}, at: [<00000000e7e1c8ff>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000af6756ad>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4082: #0: (&tty->ldisc_sem){++++}, at: [<00000000e7e1c8ff>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000af6756ad>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor7/8739: #0: (&mm->mmap_sem){++++}, at: [<0000000094a8874b>] __do_page_fault+0x84b/0xc90 arch/x86/mm/fault.c:1362 1 lock held by syz-executor7/8741: #0: (&mm->mmap_sem){++++}, at: [<000000001cac2a16>] exit_mm kernel/exit.c:510 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000001cac2a16>] do_exit+0x4b0/0x1ad0 kernel/exit.c:852 1 lock held by syz-executor7/8756: #0: (&mm->mmap_sem){++++}, at: [<000000001cac2a16>] exit_mm kernel/exit.c:510 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000001cac2a16>] do_exit+0x4b0/0x1ad0 kernel/exit.c:852 1 lock held by syz-executor7/8764: #0: (&mm->mmap_sem){++++}, at: [<000000001cac2a16>] exit_mm kernel/exit.c:510 [inline] #0: (&mm->mmap_sem){++++}, at: [<000000001cac2a16>] do_exit+0x4b0/0x1ad0 kernel/exit.c:852 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 761 Comm: khungtaskd Not tainted 4.15.0+ #10 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:542 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8772 Comm: syz-executor7 Not tainted 4.15.0+ #10 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:mark_lock+0x67/0x1430 kernel/locking/lockdep.c:3114 RSP: 0018:ffff8801b70a6dc8 EFLAGS: 00000082 RAX: ffffed0036e14dbd RBX: 0000000000000002 RCX: 0000000000000002 RDX: ffff8801d21f69c0 RSI: dffffc0000000000 RDI: ffff8801d21f6100 RBP: ffff8801b70a6ef0 R08: 1ffff10036e14dbd R09: 0000000000000004 R10: 0000000000000000 R11: 0000000000000004 R12: ffff8801d21f69a0 R13: 0000000000000001 R14: 0000000000000001 R15: ffff8801d21f6100 FS: 00007f31278e0700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000041b9e0 CR3: 00000001da859001 CR4: 00000000001606f0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: mark_irqflags kernel/locking/lockdep.c:3039 [inline] __lock_acquire+0x601/0x3e00 kernel/locking/lockdep.c:3388 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_mmap+0x6b2/0x1b70 kernel/events/core.c:5290 call_mmap include/linux/fs.h:1786 [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:355 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:00007f31278dfc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f31278e0700 RCX: 0000000000453299 RDX: 0000000000000000 RSI: 0000000000002000 RDI: 0000000020007000 RBP: 00007fff18003780 R08: 0000000000000012 R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000212 R12: 0000000000000000 R13: 00007fff180036ff R14: 00007f31278e09c0 R15: 0000000000000002 Code: f8 fe ff ff b3 8a b5 41 48 c7 85 00 ff ff ff e0 d3 7c 86 48 c7 85 08 ff ff ff a0 32 56 81 41 bd 01 00 00 00 48 89 bd f0 fe ff ff 00 f1 f1 f1 f1 41 d3 e5 c7 40 04 04 f2 f2 f2 c7 40 08 f2 f2