INFO: task syz-executor2:1708 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-executor2   D28824  1708   2118 0x80000000
 ffff8801c90c97c0 ffff8801a1a6e880 ffff8801a1a6e880 ffff8801997daf80
 ffff8801db721018 ffff8801cbbd7b10 ffffffff827f93d2 ffff8801cbbd7ae8
 ffffffff81206ab7 0000000000000000 00ff8801c90ca068 ffff8801db7218f0
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
 [<ffffffff810e6681>] exit_mm kernel/exit.c:480 [inline]
 [<ffffffff810e6681>] do_exit+0x3c1/0x29d0 kernel/exit.c:820
 [<ffffffff810ed121>] do_group_exit+0x111/0x300 kernel/exit.c:937
 [<ffffffff810ed32d>] SYSC_exit_group kernel/exit.c:948 [inline]
 [<ffffffff810ed32d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:946
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82809653>] 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: [<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/2028:
 #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-executor0/30199:
 #0:  (&sig->cred_guard_mutex){+.+.+.}, at: [<ffffffff81520d63>] prepare_bprm_creds+0x53/0x110 fs/exec.c:1369
1 lock held by syz-executor2/1708:
 #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-executor2/1714:
 #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-executor2/1725:
 #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-executor2/1726:
 #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-executor2/1728:
 #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 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.135+ #60
 ffff8801d9907d08 ffffffff81b36bf9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff81098330 ffff8801d9907d40
 ffffffff81b41d09 0000000000000000 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1727 Comm: syz-executor2 Not tainted 4.9.135+ #60
task: ffff8801997d97c0 task.stack: ffff8801a2678000
RIP: 0010:[<ffffffff812077b3>] 
c [<ffffffff812077b3>] __lock_acquire+0x6f3/0x4a10 kernel/locking/lockdep.c:3335
RSP: 0018:ffff8801a267f900  EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff8801997da098 RCX: 1ffff100332fb417
RDX: 1ffff100332fb413 RSI: ffff8801997da098 RDI: ffffffff83ccbd00
RBP: ffff8801a267fab0 R08: ffff8801997da0b8 R09: 0000000000000001
R10: ffff8801997d97c0 R11: 0000000000000000 R12: 00000000000003a4
R13: 0000000000000001 R14: 00000000000003a4 R15: c069dba3f096c9f2
FS:  00007f42cb30e700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c4326e1000 CR3: 00000001ceb8b000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801997da068
c 0000000000000046
c ffff8801997d97c0
c ffff8801db721018
c
 dffffc0000000000
c ffff8801cee80280
c ffff8801a267f970
c ffffffff81b9ba7b
c
 ffffffff81b9ba7b
c ffffffff82a92e20
c ffffffff83ccbcd0
c dffffc0000000000
c
Call Trace:
 [<ffffffff8120c5e0>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
 [<ffffffff827fd030>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
 [<ffffffff827fd030>] mutex_lock_nested+0xc0/0x900 kernel/locking/mutex.c:621
 [<ffffffff813d9757>] perf_mmap+0x4f7/0x1430 kernel/events/core.c:5265
 [<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: 
c85 
c42 
c2f 
c00 
c00 
c4d 
c8b 
cba 
ca0 
c08 
c00 
c00 
c45 
c31 
cdb 
c45 
c85 
ced 
c41 
c0f 
c94 
cc3 
c48 
cb8 
c00 
c00 
c00 
c00 
c00 
cfc 
cff 
cdf 
c48 
c89 
cda 
c48 
cc1 
cea 
c03 
c80 
c3c 
c02 
c00 
c<0f> 
c85 
cc3 
c2c 
c00 
c00 
c48 
c8b 
c94 
c24 
c80 
c00 
c00 
c00 
c4c 
c89 
c3b 
c48 
cb8 
c00 
c00 
c