[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[   19.835918] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available)
[?25l[?1c7[ ok 8[?25h[?0c.
[   20.145313] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available)
[   20.462757] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available)

Debian GNU/Linux 7 syzkaller ttyS0

syzkaller login: [   21.562245] random: sshd: uninitialized urandom read (32 bytes read, 128 bits of entropy available)
[   21.659474] random: nonblocking pool is initialized
Warning: Permanently added '10.128.10.12' (ECDSA) to the list of known hosts.
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[   27.318326] page:ffffea0002dc8000 count:2 mapcount:0 mapping:          (null) index:0x0
[   27.332120] flags: 0x4000000000004004(referenced|head)
[   27.337962] page dumped because: VM_BUG_ON_PAGE(!PageLocked(page))
[   27.344525] ------------[ cut here ]------------
[   27.349264] kernel BUG at mm/filemap.c:819!
[   27.353559] invalid opcode: 0000 [#1] PREEMPT SMP KASAN
[   27.359411] Dumping ftrace buffer:
[   27.362919]    (ftrace buffer empty)
[   27.366610] Modules linked in:
[   27.369900] CPU: 1 PID: 3779 Comm: syz-executor756 Not tainted 4.4.131-g6ec0e3f #35
[   27.377664] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   27.386999] task: ffff8800af91c800 task.stack: ffff8801d9620000
[   27.393027] RIP: 0010:[<ffffffff8141de15>]  [<ffffffff8141de15>] unlock_page+0x115/0x150
[   27.401355] RSP: 0018:ffff8801d96277d8  EFLAGS: 00010293
[   27.406775] RAX: ffffffff83a6e7c0 RBX: ffffea0002dc8000 RCX: 0000000000000000
[   27.414021] RDX: 0000000000000000 RSI: ffffffff81513249 RDI: ffff8800af91d0dc
[   27.421263] RBP: ffff8801d96277f8 R08: 0000000000000001 R09: 0000000000000000
[   27.428506] R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
[   27.435749] R13: ffff8801d9627aa8 R14: ffffea0002dc9480 R15: ffffea0002dc8008
[   27.442992] FS:  00007f0f45d05700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
[   27.451190] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   27.457043] CR2: 00000000204a4ff0 CR3: 00000001d9b52000 CR4: 00000000001606f0
[   27.464287] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   27.471532] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   27.478773] Stack:
[   27.480894]  ffffea0002dc8000 dffffc0000000000 ffff8801d9627aa8 ffffea0002dc9480
[   27.488878]  ffff8801d96278e0 ffffffff812cc1bc 0000000000000001 ffff8801d9627890
[   27.496859]  0000000000000046 ffff8801cbbe6800 00000000af91d0d8 ffff8801d9627ab8
[   27.504843] Call Trace:
[   27.507408]  [<ffffffff812cc1bc>] get_futex_key+0xadc/0xd80
[   27.513091]  [<ffffffff812cb6e0>] ? futex_lock_pi_atomic+0x2b0/0x2b0
[   27.519554]  [<ffffffff838bf2a5>] ? _raw_spin_unlock_irqrestore+0x45/0x70
[   27.526453]  [<ffffffff812cc999>] futex_wait_setup+0xd9/0x330
[   27.532311]  [<ffffffff812cc8c0>] ? futex_wake+0x460/0x460
[   27.537911]  [<ffffffff8129d143>] ? __hrtimer_init+0x143/0x1e0
[   27.543868]  [<ffffffff812cce9f>] futex_wait+0x2af/0x600
[   27.549292]  [<ffffffff812ccbf0>] ? futex_wait_setup+0x330/0x330
[   27.555412]  [<ffffffff8129b4a0>] ? clock_was_set_work+0x30/0x30
[   27.561528]  [<ffffffff812d07b2>] do_futex+0x2a2/0x1770
[   27.566862]  [<ffffffff812d0510>] ? exit_robust_list+0x220/0x220
[   27.572979]  [<ffffffff810d7ac5>] ? __do_page_fault+0x385/0xa10
[   27.579009]  [<ffffffff8122e69b>] ? trace_hardirqs_on_caller+0x38b/0x590
[   27.585827]  [<ffffffff8129a70a>] ? ktime_add_safe+0xea/0x150
[   27.591684]  [<ffffffff8129a620>] ? SyS_alarm+0x20/0x20
[   27.597022]  [<ffffffff810cbeb3>] ? kvm_clock_read+0x23/0x40
[   27.602793]  [<ffffffff810cbed9>] ? kvm_clock_get_cycles+0x9/0x10
[   27.608994]  [<ffffffff812d1f04>] ? SyS_futex+0x284/0x300
[   27.614502]  [<ffffffff812d1e70>] SyS_futex+0x1f0/0x300
[   27.619842]  [<ffffffff812d1c80>] ? do_futex+0x1770/0x1770
[   27.625437]  [<ffffffff838c08d8>] ? retint_user+0x18/0x3c
[   27.630948]  [<ffffffff81003017>] ? trace_hardirqs_on_thunk+0x17/0x19
[   27.637501]  [<ffffffff838bfd25>] entry_SYSCALL_64_fastpath+0x22/0x9e
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[   27.644050] Code: e8 48 8d 04 c0 49 8d 3c c6 e8 48 c0 df ff 5b 41 5c 41 5d 41 5e 5d c3 e8 da 33 f3 ff 48 c7 c6 60 aa a9 83 48 89 df e8 4b eb 06 00 <0f> 0b 48 89 df e8 f1 b1 0d 00 e9 0a ff ff ff e8 e7 b1 0d 00 e9 
[   27.670874] RIP  [<ffffffff8141de15>] unlock_page+0x115/0x150
[   27.676865]  RSP <ffff8801d96277d8>
[   27.681006] ---[ end trace 60177418d0ff216b ]---
[   27.686157] Kernel panic - not syncing: Fatal exception
[   27.692097] Dumping ftrace buffer:
[   27.695617]    (ftrace buffer empty)
[   27.699298] Kernel Offset: disabled
[   27.702892] Rebooting in 86400 seconds..