INFO: task syz-executor.0:26390 blocked for more than 140 seconds.
      Not tainted 4.14.134+ #18
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28808 26390   1964 0x80000000
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline]
 rwsem_down_read_failed+0x22a/0x3c0 kernel/locking/rwsem-xadd.c:309
 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:66 [inline]
 down_read+0x45/0xa0 kernel/locking/rwsem.c:26
 exit_mm kernel/exit.c:511 [inline]
 do_exit+0x575/0x2a20 kernel/exit.c:861
INFO: task syz-executor.0:26392 blocked for more than 140 seconds.
      Not tainted 4.14.134+ #18
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28912 26392   1964 0x80000000
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline]
 rwsem_down_read_failed+0x22a/0x3c0 kernel/locking/rwsem-xadd.c:309
 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:66 [inline]
 down_read+0x45/0xa0 kernel/locking/rwsem.c:26
 exit_mm kernel/exit.c:511 [inline]
 do_exit+0x575/0x2a20 kernel/exit.c:861

Showing all locks held in the system:
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<        (ptrval)>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
2 locks held by getty/1759:
 #0:  (&tty->ldisc_sem){++++}, at: [<        (ptrval)>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<        (ptrval)>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.0/26390:
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] exit_mm kernel/exit.c:511 [inline]
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] do_exit+0x575/0x2a20 kernel/exit.c:861
1 lock held by syz-executor.0/26392:
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] exit_mm kernel/exit.c:511 [inline]
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] do_exit+0x575/0x2a20 kernel/exit.c:861

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

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.134+ #18
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 26393 Comm: syz-executor.0 Not tainted 4.14.134+ #18
task:         (ptrval) task.stack:         (ptrval)
RIP: 0010:__lock_acquire+0x1/0x42e0 kernel/locking/lockdep.c:3344
RSP: 0018:ffff8881c1467a58 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8881c4e42f00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881c9189440
RBP: ffff8881c9189440 R08: 0000000000000001 R09: 0000000000000000
R10: fffffbfff4445941 R11: ffffffffa222ca0b R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f43142ec700(0000) GS:ffff8881dbb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000b7c308 CR3: 00000001c76d0005 CR4: 00000000001606a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x12b/0x360 kernel/locking/lockdep.c:3991
 __mutex_lock_common kernel/locking/mutex.c:756 [inline]
 __mutex_lock+0xf7/0x13e0 kernel/locking/mutex.c:893
 perf_mmap+0x50d/0x1480 kernel/events/core.c:5416
 call_mmap include/linux/fs.h:1793 [inline]
 mmap_region+0x7d9/0xfb0 mm/mmap.c:1732
 do_mmap+0x548/0xb80 mm/mmap.c:1510
 do_mmap_pgoff include/linux/mm.h:2209 [inline]
 vm_mmap_pgoff+0x177/0x1c0 mm/util.c:333
 SYSC_mmap_pgoff mm/mmap.c:1560 [inline]
 SyS_mmap_pgoff+0xf4/0x1b0 mm/mmap.c:1518
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
Code: c7 a0 a5 45 a3 e8 50 f9 33 00 e9 87 fe ff ff 90 66 2e 0f 1f 84 00 00 00 00 00 48 8b 3c 24 e9 b7 fa ff ff 0f 1f 80 00 00 00 00 55 <48> 89 e5 41 57 49 89 ff 41 56 41 55 45 89 cd 41 54 41 89 cc 53