perf_callchain_user oops

[Dave Jones]

Not seen this one before..

Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
CPU: 1 PID: 24420 Comm: trinity-main Not tainted 4.11.0-rc3-think+ #3 
task: ffff8804f4c85440 task.stack: ffffc90001d38000
RIP: 0010:perf_callchain_user+0x11e/0x220
RSP: 0000:ffffc90001d3ba98 EFLAGS: 00010246
RAX: ffff88044c59c2a8 RBX: ffffc90001d3bae8 RCX: 0000562bce3f6e40
RDX: 0000562bce3f6e40 RSI: 00007fffffffeff0 RDI: 0000000000000000
RBP: ffffc90001d3bab8 R08: 00000000bffffff0 R09: 00000000ffffdff0
R10: 0000000000002faa R11: 0000000000002fab R12: ffff8804f4c85440
R13: ffffc90001d3bf58 R14: ffffc90001d3bf58 R15: 0000000000000000
FS:  00007f34b3969b40(0000) GS:ffff880507a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88044c5b4000 CR3: 000000044c584000 CR4: 00000000001406e0
DR0: 00007f34b382e000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 get_perf_callchain+0x258/0x2b0
 perf_callchain+0x79/0x80
 perf_prepare_sample+0x27e/0x360
 perf_event_output_forward+0x75/0x160
 ? perf_prepare_sample+0x360/0x360
 ? sched_clock_cpu+0x13/0xe0
 __perf_event_overflow+0x54/0xf0
 perf_swevent_overflow+0x9a/0xc0
 perf_swevent_event+0x60/0x80
 ___perf_sw_event+0x152/0x290
 ? ___perf_sw_event+0x32/0x290
 ? debug_smp_processor_id+0x17/0x20
 ? get_lock_stats+0x19/0x50
 ? filemap_map_pages+0x2b7/0x550
 ? filemap_map_pages+0x5/0x550
 ? _raw_spin_unlock+0x31/0x50
 ? debug_smp_processor_id+0x17/0x20
 ? get_lock_stats+0x19/0x50
 __perf_sw_event+0x43/0x90
 __do_page_fault+0x322/0x4f0
 do_page_fault+0x20/0x70
 page_fault+0x1f/0x30
RIP: 0033:0x7f34b3232ca0
RSP: 002b:00007ffe946e1ae8 EFLAGS: 00010206
RAX: 0000562bce3431b0 RBX: 0000562bcdb73210 RCX: 000000000000001d
RDX: 000000000000001d RSI: 0000562bcdb73250 RDI: 0000562bce3431b0
RBP: 0000562bce3f6e40 R08: 00000000000000b1 R09: 00000000000000ff
R10: 00000000bcbf40b2 R11: 00000000834e0b5f R12: 0000562bcdb732b0
R13: 0000000000000003 R14: 0000000000002804 R15: 00007ffe946e1e80
Code: f8 48 8b 0a 85 c0 0f 85 e7 00 00 00 48 8b 52 08 85 c0 0f 85 db 00 00 00 80 7b 12 00 75 aa 48 8b 03 4c 8b 10 4d 8d 5a 01 4c 89 18 <4a> 89 54 d0 08 8b 43 0c 83 c0 01 89 43 0c eb 90 41 8b bd 88 00 
CR2: ffff88044c5b4000