INFO: task syz-executor288:2541 blocked for more than 140 seconds.
      Not tainted 4.9.135+ #60
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor288 D28584  2541   2152 0x00000004
 ffff8801c4be17c0 0000000000000000 ffff8801ca1d6e00 ffffffff8302a180
 ffff8801db621018 ffff8801ca2afc50 ffffffff827f93d2 ffff8801ca2afc28
 ffffffff81206ab7 0000000000000000 00ff8801c4be2068 ffff8801db6218f0
Call Trace:
 [<ffffffff827fa8ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff8280565c>] rwsem_down_read_failed+0x26c/0x400 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81b69148>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff82803432>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff82803432>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff810b2e6b>] __do_page_fault+0x7db/0xa60 arch/x86/mm/fault.c:1342
 [<ffffffff810b3147>] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1469
 [<ffffffff8280a675>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:951

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bb4c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bb4c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe314>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2022:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82807722>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81d2b032>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor288/2541:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810b2e6b>] __do_page_fault+0x7db/0xa60 arch/x86/mm/fault.c:1342
1 lock held by syz-executor288/2542:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6681>] exit_mm kernel/exit.c:480 [inline]
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6681>] do_exit+0x3c1/0x29d0 kernel/exit.c:820
1 lock held by syz-executor288/2543:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6681>] exit_mm kernel/exit.c:480 [inline]
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6681>] do_exit+0x3c1/0x29d0 kernel/exit.c:820

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.135+ #60
 ffff8801d9907d08 ffffffff81b36bf9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff81098330 ffff8801d9907d40
 ffffffff81b41d09 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b36bf9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b36bf9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b41d09>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b41c9c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff81098434>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c0dd>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c0dd>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c0dd>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c0dd>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff811428dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8280981c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2544 Comm: syz-executor288 Not tainted 4.9.135+ #60
task: ffff8801c4be4740 task.stack: ffff8801c9cb0000
RIP: 0010:[<ffffffff81205761>] 
c [<ffffffff81205761>] mark_lock+0x1/0x1290 kernel/locking/lockdep.c:3032
RSP: 0018:ffff8801c9cb7af8  EFLAGS: 00000002
RAX: 0000000000000004 RBX: 0000000000000000 RCX: 1ffff1003897ca02
RDX: 0000000000000006 RSI: ffff8801c4be4ff0 RDI: ffff8801c4be4740
RBP: ffff8801c9cb7b48 R08: ffff8801c4be5010 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c4be4ff0
R13: ffffed003897c9fd R14: ffff8801c4be4740 R15: dffffc0000000000
FS:  00007fc08a2be700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc160e55fe0 CR3: 00000001ca5ac000 CR4: 00000000001606b0
Stack:
 ffff8801c9cb7b48
c ffffffff81206ab7
c ffff8801ca3de060
c ffff8801c4be4fe8
c
 0000000600000007
c ffff8801c4be4740
c ffffffff8280209b
c 1ffff10039396f72
c
 0000000000000246
c ffff8801c9cb7bb0
c ffff8801c9cb7b68
c ffffffff81206eab
c
Call Trace:
 [<ffffffff81206eab>] __trace_hardirqs_on_caller kernel/locking/lockdep.c:2689 [inline]
 [<ffffffff81206eab>] trace_hardirqs_on_caller+0x38b/0x590 kernel/locking/lockdep.c:2736
 [<ffffffff812070bd>] trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2743
 [<ffffffff8280209b>] __mutex_unlock_common_slowpath kernel/locking/mutex.c:753 [inline]
 [<ffffffff8280209b>] __mutex_unlock_slowpath+0x25b/0x3c0 kernel/locking/mutex.c:765
 [<ffffffff82802209>] mutex_unlock+0x9/0x10 kernel/locking/mutex.c:437
 [<ffffffff813d98aa>] perf_mmap+0x64a/0x1430 kernel/events/core.c:5278
 [<ffffffff814b417c>] mmap_region+0x80c/0xf90 mm/mmap.c:1726
 [<ffffffff814b4e3d>] do_mmap+0x53d/0xbb0 mm/mmap.c:1505
 [<ffffffff81469e48>] do_mmap_pgoff include/linux/mm.h:2032 [inline]
 [<ffffffff81469e48>] vm_mmap_pgoff+0x168/0x1b0 mm/util.c:329
 [<ffffffff814af4ee>] SYSC_mmap_pgoff mm/mmap.c:1555 [inline]
 [<ffffffff814af4ee>] SyS_mmap_pgoff+0xfe/0x1b0 mm/mmap.c:1513
 [<ffffffff8105d376>] SYSC_mmap arch/x86/kernel/sys_x86_64.c:96 [inline]
 [<ffffffff8105d376>] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:87
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82809653>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c<4c> 
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c