INFO: task syz-executor0:5550 blocked for more than 140 seconds.
      Not tainted 4.9.132+ #51
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D28568  5550   2266 0x80000000
 ffff8801ca552f80 ffff8801d4bba680 ffff8801d4bba680 ffff8801ca554740
 ffff8801db621018 ffff8801c9bf7b10 ffffffff827f36e2 ffff8801c9bf7ae8
 ffffffff81206c17 0000000000000000 00ff8801ca553828 ffff8801db6218f0
Call Trace:
 [<ffffffff827f4c0f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff827ff96c>] rwsem_down_read_failed+0x26c/0x400 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81b69708>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff827fd742>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff827fd742>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff810e6841>] exit_mm kernel/exit.c:480 [inline]
 [<ffffffff810e6841>] do_exit+0x3c1/0x29d0 kernel/exit.c:820
 [<ffffffff810ed2e1>] do_group_exit+0x111/0x300 kernel/exit.c:937
 [<ffffffff810ed4ed>] SYSC_exit_group kernel/exit.c:948 [inline]
 [<ffffffff810ed4ed>] SyS_exit_group+0x1d/0x20 kernel/exit.c:946
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82803953>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bc8c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bc8c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe454>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2034:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82801a32>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d2b442>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor0/5550:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6841>] exit_mm kernel/exit.c:480 [inline]
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6841>] do_exit+0x3c1/0x29d0 kernel/exit.c:820
1 lock held by syz-executor0/5551:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6841>] exit_mm kernel/exit.c:480 [inline]
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6841>] do_exit+0x3c1/0x29d0 kernel/exit.c:820
1 lock held by syz-executor0/5563:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6841>] exit_mm kernel/exit.c:480 [inline]
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff810e6841>] do_exit+0x3c1/0x29d0 kernel/exit.c:820

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.132+ #51
 ffff8801d9907d08 ffffffff81b371b9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810984f0 ffff8801d9907d40
 ffffffff81b422c9 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b371b9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b371b9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b422c9>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4225c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810985f4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c21d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c21d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c21d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c21d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff81142a9d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82803b1c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5562 Comm: syz-executor0 Not tainted 4.9.132+ #51
task: ffff8801c9572f80 task.stack: ffff8801c9bd0000
RIP: 0010:[<ffffffff81205970>] 
c [<ffffffff81205970>] mark_lock+0xb0/0x1290 kernel/locking/lockdep.c:3039
RSP: 0018:ffff8801c9bd7a60  EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff8801c9573858 RCX: 1ffff100392ae70f
RDX: 1ffffffff0798f9e RSI: ffff8801c9573858 RDI: ffffffff83cc7cf0
RBP: ffff8801c9bd7aa8 R08: ffff8801c9573878 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff83cc7cc0
R13: 0000000000000040 R14: 0000000000000006 R15: ffff8801c9572f80
FS:  00007f20951aa700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000c9c308 CR3: 00000001c9b59000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000246
c ffff8801c9572f80
c ffffffff830cc2e0
c d4e84e40c231a289
c
 0000000000000001
c ffff8801c9573830
c ffffed00392ae705
c ffff8801c9572f80
c
 dffffc0000000000
c ffff8801c9bd7af8
c ffffffff81206c17
c 0000000000000246
c
Call Trace:
 [<ffffffff81206c17>] mark_held_locks+0xc7/0x130 kernel/locking/lockdep.c:2660
 [<ffffffff8120700b>] __trace_hardirqs_on_caller kernel/locking/lockdep.c:2689 [inline]
 [<ffffffff8120700b>] trace_hardirqs_on_caller+0x38b/0x590 kernel/locking/lockdep.c:2736
 [<ffffffff8120721d>] trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2743
 [<ffffffff827f7937>] __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 [<ffffffff827f7937>] mutex_lock_nested+0x6b7/0x900 kernel/locking/mutex.c:621
 [<ffffffff813d9897>] perf_mmap+0x4f7/0x1430 kernel/events/core.c:5265
 [<ffffffff814b42bc>] mmap_region+0x80c/0xf90 mm/mmap.c:1726
 [<ffffffff814b4f7d>] do_mmap+0x53d/0xbb0 mm/mmap.c:1505
 [<ffffffff81469f88>] do_mmap_pgoff include/linux/mm.h:2032 [inline]
 [<ffffffff81469f88>] vm_mmap_pgoff+0x168/0x1b0 mm/util.c:329
 [<ffffffff814af62e>] SYSC_mmap_pgoff mm/mmap.c:1555 [inline]
 [<ffffffff814af62e>] SyS_mmap_pgoff+0xfe/0x1b0 mm/mmap.c:1513
 [<ffffffff8105d356>] SYSC_mmap arch/x86/kernel/sys_x86_64.c:96 [inline]
 [<ffffffff8105d356>] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:87
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82803953>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c<4d> 
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c