ffffffff8165fe47[  259.398953] kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 13804 Comm: syz-executor2 Not tainted 4.9.61-gdac2e9c #88
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cc198000 task.stack: ffff8801a6080000
RIP: 0010:[<ffffffff8144db91>] 
 [<ffffffff8144db91>] __read_once_size include/linux/compiler.h:243 [inline]
 [<ffffffff8144db91>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
 [<ffffffff8144db91>] page_ref_count include/linux/page_ref.h:66 [inline]
 [<ffffffff8144db91>] put_page_testzero include/linux/mm.h:445 [inline]
 [<ffffffff8144db91>] __free_pages+0x21/0x80 mm/page_alloc.c:3901
RSP: 0018:ffff8801a6087ab0  EFLAGS: 00010a07
RAX: dffffc0000000000 RBX: dead4ead00000000 RCX: ffffc90004188000
RDX: 1bd5a9d5a0000003 RSI: 0000000000000001 RDI: dead4ead0000001c
RBP: ffff8801a6087ac0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8801cc198000 R12: 0000000000000004
R13: 0000000000000020 R14: ffff8801a5b72100 R15: dffffc0000000000
FS:  00007f75a6369700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020e75000 CR3: 00000001c47e8000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff838ab7f9
 ffff8801a5b72258 ffff8801a6087b20 ffffffff8265fd31[  259.399095]  ffff8801a5b72270
 ffffed0034b6e44b ffffed0034b6e44e ffff8801a5b72268[  259.399107]  dead4ead00000000
 ffff8801a5b72240 0000000000000000 0000000000000000[  259.399118] Call Trace:
 [<ffffffff8265fd31>] sg_remove_scat.isra.20+0x1c1/0x2d0 drivers/scsi/sg.c:1954
 [<ffffffff826600f5>] sg_finish_rem_req+0x2b5/0x340 drivers/scsi/sg.c:1836
 [<ffffffff826604d6>] sg_new_read.isra.21+0x356/0x3e0 drivers/scsi/sg.c:567
 [<ffffffff82661d96>] sg_read+0x8a6/0x1400 drivers/scsi/sg.c:456
 [<ffffffff8156c793>] __vfs_read+0x103/0x670 fs/read_write.c:452
 [<ffffffff8156dd27>] vfs_read+0x107/0x330 fs/read_write.c:475
 [<ffffffff815719c9>] SYSC_read fs/read_write.c:591 [inline]
 [<ffffffff815719c9>] SyS_read+0xd9/0x1b0 fs/read_write.c:584
 [<ffffffff838aadc5>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
ff 66 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 53 48 89 fb 48 83 c7 1c 48 89 fa 48 83 ec 08 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 3d [  259.399477] RIP 
 [<ffffffff8144db91>] __read_once_size include/linux/compiler.h:243 [inline]
 [<ffffffff8144db91>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
 [<ffffffff8144db91>] page_ref_count include/linux/page_ref.h:66 [inline]
 [<ffffffff8144db91>] put_page_testzero include/linux/mm.h:445 [inline]
 [<ffffffff8144db91>] __free_pages+0x21/0x80 mm/page_alloc.c:3901
---[ end trace db04c4c1df90fb8d ]---
Kernel panic - not syncing: Fatal exception
 0000000000000f52 ffff8801d56b6968 ffff8801d56b68a0
 [<ffffffff81d91589>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d91589>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8165fe47>] handle_userfault+0xa37/0x1300 fs/userfaultfd.c:323
 [<ffffffff814cf571>] do_anonymous_page mm/memory.c:2747 [inline]
 [<ffffffff814cf571>] handle_pte_fault mm/memory.c:3488 [inline]
 [<ffffffff814cf571>] __handle_mm_fault mm/memory.c:3577 [inline]
 [<ffffffff814cf571>] handle_mm_fault+0x1fd1/0x2530 mm/memory.c:3614
 [<ffffffff810e0447>] __do_page_fault+0x5b7/0xd70 arch/x86/mm/fault.c:1396
 [<ffffffff810e0c27>] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1460
 [<ffffffff838abf98>] page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1012
 [<ffffffff8143312c>] generic_perform_write+0x1dc/0x500 mm/filemap.c:2731
 [<ffffffff8143ad08>] __generic_file_write_iter+0x348/0x570 mm/filemap.c:2866
 [<ffffffff8143b205>] generic_file_write_iter+0x2d5/0x600 mm/filemap.c:2894
 [<ffffffff8156a35f>] new_sync_write fs/read_write.c:499 [inline]
 [<ffffffff8156a35f>] __vfs_write+0x4bf/0x680 fs/read_write.c:512
 [<ffffffff8156e0c0>] vfs_write+0x170/0x4e0 fs/read_write.c:560
 [<ffffffff81571b79>] SYSC_write fs/read_write.c:607 [inline]
 [<ffffffff81571b79>] SyS_write+0xd9/0x1b0 fs/read_write.c:599
 [<ffffffff81006517>] do_syscall_64+0x197/0x490 arch/x86/entry/common.c:280
 [<ffffffff838aae8d>] entry_SYSCALL64_slow_path+0x25/0x25
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..