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: 0 PID: 4082 Comm: syz-executor4 Not tainted 4.9.62-gf09daf1 #91
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c7996000 task.stack: ffff8801d8370000
RIP: 0010:[<ffffffff8144fce1>] 
 [<ffffffff8144fce1>] __read_once_size include/linux/compiler.h:243 [inline]
 [<ffffffff8144fce1>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
 [<ffffffff8144fce1>] page_ref_count include/linux/page_ref.h:66 [inline]
 [<ffffffff8144fce1>] put_page_testzero include/linux/mm.h:445 [inline]
 [<ffffffff8144fce1>] __free_pages+0x21/0x80 mm/page_alloc.c:3901
RSP: 0018:ffff8801d8377ab0  EFLAGS: 00010a07
RAX: dffffc0000000000 RBX: dead4ead00000000 RCX: ffffc900019b8000
RDX: 1bd5a9d5a0000003 RSI: 0000000000000001 RDI: dead4ead0000001c
RBP: ffff8801d8377ac0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8801c7996000 R12: 0000000000000004
R13: 0000000000000020 R14: ffff8801d80ea100 R15: dffffc0000000000
FS:  00007f63d62c3700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000208ba000 CR3: 00000001a902a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000001
 ffff8801d80ea258 ffff8801d8377b20 ffffffff826635a1[   41.630611]  ffff8801d80ea270
 ffffed003b01d44b ffffed003b01d44e ffff8801d80ea268[   41.630622]  dead4ead00000000
 ffff8801d80ea240 0000000000000000 0000000000000000[   41.630632] Call Trace:
 [<ffffffff826635a1>] sg_remove_scat.isra.20+0x1c1/0x2d0 drivers/scsi/sg.c:1954
 [<ffffffff82663965>] sg_finish_rem_req+0x2b5/0x340 drivers/scsi/sg.c:1836
 [<ffffffff82663d46>] sg_new_read.isra.21+0x356/0x3e0 drivers/scsi/sg.c:567
 [<ffffffff8266561d>] sg_read+0x8bd/0x1440 drivers/scsi/sg.c:456
 [<ffffffff8156c193>] __vfs_read+0x103/0x670 fs/read_write.c:452
 [<ffffffff8156ff2e>] vfs_read+0x11e/0x380 fs/read_write.c:475
 [<ffffffff81573c59>] SYSC_read fs/read_write.c:591 [inline]
 [<ffffffff81573c59>] SyS_read+0xd9/0x1b0 fs/read_write.c:584
 [<ffffffff838af485>] 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 [   41.630977] RIP 
 [<ffffffff8144fce1>] __read_once_size include/linux/compiler.h:243 [inline]
 [<ffffffff8144fce1>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
 [<ffffffff8144fce1>] page_ref_count include/linux/page_ref.h:66 [inline]
 [<ffffffff8144fce1>] put_page_testzero include/linux/mm.h:445 [inline]
 [<ffffffff8144fce1>] __free_pages+0x21/0x80 mm/page_alloc.c:3901
---[ end trace 922cdf81d1fad910 ]---
Kernel panic - not syncing: Fatal exception
 ffff8801d25d76b0 ffff8801a7c9ed80 ffff8801d25d76d8
 ffffffff816623c7 0000000000000647 ffff8801d098b968 ffff8801d098b8a0
Call Trace:
 [<ffffffff81d94429>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d94429>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff816623c7>] handle_userfault+0xa37/0x1300 fs/userfaultfd.c:323
 [<ffffffff814d16c1>] do_anonymous_page mm/memory.c:2747 [inline]
 [<ffffffff814d16c1>] handle_pte_fault mm/memory.c:3488 [inline]
 [<ffffffff814d16c1>] __handle_mm_fault mm/memory.c:3577 [inline]
 [<ffffffff814d16c1>] handle_mm_fault+0x1fd1/0x2530 mm/memory.c:3614
 [<ffffffff810e1447>] __do_page_fault+0x5b7/0xd70 arch/x86/mm/fault.c:1396
 [<ffffffff810e1c27>] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1460
 [<ffffffff838b0658>] page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1012
 [<ffffffff8143527c>] generic_perform_write+0x1dc/0x500 mm/filemap.c:2731
 [<ffffffff8143ce58>] __generic_file_write_iter+0x348/0x570 mm/filemap.c:2866
 [<ffffffff8143d355>] generic_file_write_iter+0x2d5/0x600 mm/filemap.c:2894
 [<ffffffff8156e9ef>] new_sync_write fs/read_write.c:499 [inline]
 [<ffffffff8156e9ef>] __vfs_write+0x4bf/0x680 fs/read_write.c:512
 [<ffffffff81570319>] vfs_write+0x189/0x530 fs/read_write.c:560
 [<ffffffff81573e09>] SYSC_write fs/read_write.c:607 [inline]
 [<ffffffff81573e09>] SyS_write+0xd9/0x1b0 fs/read_write.c:599
 [<ffffffff838af485>] entry_SYSCALL_64_fastpath+0x23/0xc6
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..