BUG: unable to handle kernel NULL pointer dereference at 0000000062f76c2c
IP: qlist_free_all+0x37/0x160 mm/kasan/quarantine.c:163
PGD 1d142c067 P4D 1d142c067 PUD 1d36ab067 PMD 0 
Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
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Modules linked in:
CPU: 0 PID: 3812 Comm: kworker/u4:5 Not tainted 4.15.0-rc2+ #116
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound call_usermodehelper_exec_work
task: 0000000086da39ca task.stack: 000000008ceadbc0
RIP: 0010:qlist_free_all+0x37/0x160 mm/kasan/quarantine.c:163
RSP: 0018:ffff8801d8d8e728 EFLAGS: 00010246
RAX: ffffffff85156dd5 RBX: 0000000000000286 RCX: 0000000000000000
RDX: ffffea0000145580 RSI: ffffea000014559f RDI: 0000000000000286
RBP: ffff8801d8d8e760 R08: 1ffff1003b1b1cb3 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff85156dd5 R15: ffffffff85ecb440
FS:  0000000000000000(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000104 CR3: 00000001acd38000 CR4: 00000000001406f0
Call Trace:
 quarantine_reduce+0x141/0x170 mm/kasan/quarantine.c:259
 kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:536
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc mm/slab.c:3385 [inline]
 kmem_cache_alloc+0x11b/0x760 mm/slab.c:3545
 dup_fd+0x110/0xdf0 fs/file.c:285
 copy_files kernel/fork.c:1301 [inline]
 copy_process.part.36+0x1f74/0x4ae0 kernel/fork.c:1741
 copy_process kernel/fork.c:1566 [inline]
 _do_fork+0x1ef/0xff0 kernel/fork.c:2045
 kernel_thread+0x34/0x40 kernel/fork.c:2107
 call_usermodehelper_exec_sync kernel/umh.c:123 [inline]
 call_usermodehelper_exec_work+0xfe/0x2c0 kernel/umh.c:175
 process_one_work+0xbfd/0x1be0 kernel/workqueue.c:2112
 worker_thread+0x223/0x1990 kernel/workqueue.c:2246
 kthread+0x37a/0x440 kernel/kthread.c:238
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:441
Code: 55 48 89 e5 41 57 41 56 41 55 41 54 49 c7 c7 40 b4 ec 85 53 49 89 f4 48 83 ec 10 48 89 7d c8 4d 85 e4 4d 89 e5 0f 84 c8 00 00 00 <49> 63 95 04 01 00 00 4c 8b 30 48 29 d0 49 83 3f 00 48 89 c6 0f 
RIP: qlist_free_all+0x37/0x160 mm/kasan/quarantine.c:163 RSP: ffff8801d8d8e728
CR2: 0000000000000104
---[ end trace 3cb2b3b341ad93ab ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
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Kernel Offset: disabled
Rebooting in 86400 seconds..