On kernel 4.14 on Samus. I don't have a repro case yet. Happened over night when I left two mahjongg games running.

ebian@stretch:~$ [27501.933985] gnome-mahjongg: Corrupted page table at address 7f3cb8e6c000                
[27501.934130] PGD 10fd83067 P4D 10fd83067 PUD 1674d7067 PMD 10481d067 PTE 8000008000000227                  
[27501.934130] Bad pagetable: 000f [#1] PREEMPT SMP   
[27501.934130] CPU: 2 PID: 7530 Comm: gnome-mahjongg Not tainted 4.14.0-01423-g2d4495d436d2 #41              
[27501.934130] task: ffff88010fdd3800 task.stack: ffffc90000274000                                           
[27501.934130] RIP: 0033:0x7f3cbfb954db               
[27501.934130] RSP: 002b:00007fff75a6c288 EFLAGS: 00010202                                                   
[27501.934130] RAX: 00007f3cb8e6c040 RBX: 0000000000001dc0 RCX: 00007f3cb3db4040                             
[27501.934130] RDX: 0000000000001d80 RSI: 00007f3cb8e6bd80 RDI: 00007f3cb3db3d80                             
[27501.934130] RBP: 00007f3cb8e6db40 R08: 000000000000013c R09: 0000000000001dc0                             
[27501.934130] R10: 00007f3cb3db5b40 R11: 0000000000001dc0 R12: 0000000000001dc0                             
[27501.934130] R13: 0000000000000076 R14: 0000000000000000 R15: 0000000000000020                             
[27501.934130] FS:  00007f3cc6e3ca80(0000) GS:ffff880172700000(0000) knlGS:0000000000000000                  
[27501.934130] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033                                             
[27501.934130] CR2: 00007f3cb8e6c000 CR3: 000000016768a003 CR4: 00000000003606a0                             
[27501.934130] RIP: 0x7f3cbfb954db RSP: 00007fff75a6c288                                                     
[27501.934130] ---[ end trace ca02dcc3a29490ef ]---   
[27501.934130] BUG: sleeping function called from invalid context at ./include/linux/percpu-rwsem.h:34       
[27501.934130] in_atomic(): 0, irqs_disabled(): 1, pid: 7530, name: gnome-mahjongg                           
[27501.934130] CPU: 2 PID: 7530 Comm: gnome-mahjongg Tainted: G      D         4.14.0-01423-g2d4495d436d2 #41
[27501.934130] Call Trace: 
[27501.934130]  dump_stack+0x4d/0x63                  
[27501.934130]  ___might_sleep+0x119/0x12c            
[27501.934130]  __might_sleep+0x6a/0x71               
[27501.934130]  exit_signals+0x1e/0x131               
[27501.934130]  do_exit+0x119/0x916                   
[27501.934130]  rewind_stack_do_exit+0x17/0x20        
[27501.934130] RIP: 0033:0x7f3cbfb954db               
[27501.934130] RSP: 002b:00007fff75a6c288 EFLAGS: 00010202                                                   
[27501.934130] RAX: 00007f3cb8e6c040 RBX: 0000000000001dc0 RCX: 00007f3cb3db4040                             
[27501.934130] RDX: 0000000000001d80 RSI: 00007f3cb8e6bd80 RDI: 00007f3cb3db3d80                             
[27501.934130] RBP: 00007f3cb8e6db40 R08: 000000000000013c R09: 0000000000001dc0                             
[27501.934130] R10: 00007f3cb3db5b40 R11: 0000000000001dc0 R12: 0000000000001dc0                             
[27501.934130] R13: 0000000000000076 R14: 0000000000000000 R15: 0000000000000020