BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:LINE (2)

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
c18bb396d3d261ebbb4efbc05129c5d354c541e4 (Tue Apr 10 00:04:10 2018 +0000)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=4af447792df4648be93b

syzkaller reproducer:  
https://syzkaller.appspot.com/x/repro.syz?id=4934545564499968
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=6277896712749056
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=-1223000601505858474
compiler: gcc (GCC) 8.0.1 20180301 (experimental)

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Reported-by: syzbot+4af447792df4648be93b@xxxxxxxxxxxxxxxxxxxxxxxxx
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IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
BUG: sleeping function called from invalid context at  
arch/x86/mm/fault.c:1342
in_atomic(): 0, irqs_disabled(): 1, pid: 4512, name: blkid
1 lock held by blkid/4512:
 #0: 00000000d5b4e650 (&mm->mmap_sem){++++}, at:  
__do_page_fault+0x381/0xe40 arch/x86/mm/fault.c:1328
irq event stamp: 1812
hardirqs last  enabled at (1811): [<ffffffff87600096>]  
entry_SYSCALL_64_after_hwframe+0x52/0xb7
hardirqs last disabled at (1812): [<ffffffff87601402>]  
error_entry+0x72/0xd0 arch/x86/entry/entry_64.S:1261
softirqs last  enabled at (1804): [<ffffffff87800778>]  
__do_softirq+0x778/0xaf5 kernel/softirq.c:311
softirqs last disabled at (1797): [<ffffffff8146dd91>] invoke_softirq  
kernel/softirq.c:365 [inline]
softirqs last disabled at (1797): [<ffffffff8146dd91>] irq_exit+0x1d1/0x200  
kernel/softirq.c:405
CPU: 1 PID: 4512 Comm: blkid Not tainted 4.16.0+ #16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
BUG: unable to handle kernel paging request at 0000000041b5e1f3
PGD 1b4390067 P4D 1b4390067 PUD 0
Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4512 Comm: blkid Tainted: G        W        4.16.0+ #16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:msr_write_intercepted arch/x86/kvm/vmx.c:2126 [inline]
RIP: 0010:vmx_vcpu_run+0xa3d/0x25f0 arch/x86/kvm/vmx.c:9884
RSP: 0018:ffff8801b5d27380 EFLAGS: 00010046
==================================================================
BUG: KASAN: stack-out-of-bounds in __show_regs.cold.7+0x4e/0x54a  
arch/x86/kernel/process_64.c:79
Read of size 8 at addr ffff8801b5d27300 by task blkid/4512

CPU: 1 PID: 4512 Comm: blkid Tainted: G        W        4.16.0+ #16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:

The buggy address belongs to the page:
page:ffffea0006d749c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea0006d70101 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b5d27200: f2 f2 f2 f2 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2
 ffff8801b5d27280: f3 f3 f3 f3 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 00
> ffff8801b5d27300: f2 f2 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00
                   ^
 ffff8801b5d27380: f1 f1 f1 f1 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2
 ffff8801b5d27400: f2 f2 f2 f2 00 f2 f2 f2 f3 f3 f3 f3 00 00 00 00
==================================================================


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