netlink: 8 bytes leftover after parsing attributes in process `syz-executor2'.
INFO: task syz-executor4:14489 blocked for more than 140 seconds.
      Not tainted 4.9.133+ #54
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D28824 14489   2128 0x80000000
 ffff8801a221af80 ffff8801d419c780 ffff8801d419c780 ffff8801cacd8000
 ffff8801db621018 ffff8801cf137b10 ffffffff827f3aa2 ffff8801cf137ae8
 ffffffff81206a57 0000000000000000 00ff8801a221b828 ffff8801db6218f0
Call Trace:
 [<ffffffff827f4fcf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff827ffd2c>] rwsem_down_read_failed+0x26c/0x400 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81b695b8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff827fdb02>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff827fdb02>] 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
 [<ffffffff82803d13>] 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: [<ffffffff8131baec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131baec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe2b4>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2023:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82801df2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d2b472>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor4/14489:
 #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-executor4/14494:
 #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-executor4/14524:
 #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 4.9.133+ #54
 ffff8801d9907d08 ffffffff81b37069 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff81098330 ffff8801d9907d40
 ffffffff81b42179 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b37069>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b37069>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b42179>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4210c>] 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
 [<ffffffff8131c07d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c07d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c07d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c07d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff811428dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82803edc>] 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: 14516 Comm: syz-executor4 Not tainted 4.9.133+ #54
task: ffff8801a0858000 task.stack: ffff88019f768000
RIP: 0010:[<ffffffff81207e18>] 
c [<ffffffff81207e18>] hlock_class kernel/locking/lockdep.c:142 [inline]
RIP: 0010:[<ffffffff81207e18>] 
c [<ffffffff81207e18>] lookup_chain_cache kernel/locking/lockdep.c:2122 [inline]
RIP: 0010:[<ffffffff81207e18>] 
c [<ffffffff81207e18>] validate_chain kernel/locking/lockdep.c:2236 [inline]
RIP: 0010:[<ffffffff81207e18>] 
c [<ffffffff81207e18>] __lock_acquire+0xdb8/0x4a10 kernel/locking/lockdep.c:3345
RSP: 0018:ffff88019f76f900  EFLAGS: 00000097
RAX: 61c8864680b583eb RBX: ffff8801a08588d8 RCX: 00000000b78b3674
RDX: 0000000000000004 RSI: ffff8801a08588d8 RDI: 0000000000000000
RBP: ffff88019f76fab0 R08: ffff8801a08588f8 R09: 568d86a29d8ee127
R10: ffff8801a0858000 R11: 0000000000000000 R12: 00000000000004e5
R13: 0000000000000000 R14: 00000000949d58d0 R15: 0000000008f18857
FS:  00007f21d8806700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f60652d3140 CR3: 00000001cba75000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 00000000200001c0 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff8801a0858000
c 0000000000000000
c ffff8801a08588b0
c 0000000000000001
c
 ffff8801a08588b0
c ffffed003410b115
c ffff8801a0858000
c dffffc0000000000
c
 ffff88019f76f990
c ffffffff81206a57
c ffffffff83ceba80
c ffff88019f76f998
c
Call Trace:
 [<ffffffff8120c580>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
 [<ffffffff827f7700>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
 [<ffffffff827f7700>] mutex_lock_nested+0xc0/0x900 kernel/locking/mutex.c:621
 [<ffffffff813d96f7>] perf_mmap+0x4f7/0x1430 kernel/events/core.c:5265
 [<ffffffff814b411c>] mmap_region+0x80c/0xf90 mm/mmap.c:1726
 [<ffffffff814b4ddd>] do_mmap+0x53d/0xbb0 mm/mmap.c:1505
 [<ffffffff81469de8>] do_mmap_pgoff include/linux/mm.h:2032 [inline]
 [<ffffffff81469de8>] vm_mmap_pgoff+0x168/0x1b0 mm/util.c:329
 [<ffffffff814af48e>] SYSC_mmap_pgoff mm/mmap.c:1555 [inline]
 [<ffffffff814af48e>] 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
 [<ffffffff82803d13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c