syzbot

random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 120 bits of entropy available)
random: sshd: uninitialized urandom read (32 bytes read, 124 bits of entropy available)
random: nonblocking pool is initialized
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3780 at arch/x86/mm/pat.c:1003 untrack_pfn+0x204/0x2a0 arch/x86/mm/pat.c:1003()
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3780 Comm: syzkaller934269 Not tainted 4.4.119-g855ea74 #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 6de82625fc974cdd ffff8801d908f778 ffffffff81d0402d
 ffffffff83843b40 ffff8801d908f850 ffffffff8383da60 0000000000000009
 00000000000003eb ffff8801d908f840 ffffffff8141aaea 0000000041b58ab3
Call Trace:
 [<ffffffff81d0402d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d0402d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8141aaea>] panic+0x1aa/0x388 kernel/panic.c:112
 [<ffffffff8112d885>] warn_slowpath_common+0x125/0x140 kernel/panic.c:455
 [<ffffffff8112dae9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:492
 [<ffffffff810e8c44>] untrack_pfn+0x204/0x2a0 arch/x86/mm/pat.c:1003
 [<ffffffff8149a581>] unmap_single_vma+0xf81/0x12a0 mm/memory.c:1331
 [<ffffffff8149c201>] unmap_vmas+0x81/0xd0 mm/memory.c:1382
 [<ffffffff814a933d>] unmap_region+0x1ad/0x330 mm/mmap.c:2467
 [<ffffffff814ad63f>] do_munmap+0x70f/0xec0 mm/mmap.c:2664
 [<ffffffff814b9281>] move_vma+0x511/0x9b0 mm/mremap.c:323
 [<ffffffff814ba2ab>] mremap_to mm/mremap.c:442 [inline]
 [<ffffffff814ba2ab>] SYSC_mremap mm/mremap.c:505 [inline]
 [<ffffffff814ba2ab>] SyS_mremap+0xb8b/0xe60 mm/mremap.c:472
 [<ffffffff8377365f>] entry_SYSCALL_64_fastpath+0x1c/0x98
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..