ffff8801add44e90 ffff8801cba87b00 ffff8801add44d80 ffff8801cba87b28
 ffffffff8165e3c7[  177.474603] 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: 30761 Comm: syz-executor6 Not tainted 4.9.64-gfbb7468 #94
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d8860000 task.stack: ffff8801c6ac8000
RIP: 0010:[<ffffffff8144bce1>] 
 [<ffffffff8144bce1>] __read_once_size include/linux/compiler.h:243 [inline]
 [<ffffffff8144bce1>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
 [<ffffffff8144bce1>] page_ref_count include/linux/page_ref.h:66 [inline]
 [<ffffffff8144bce1>] put_page_testzero include/linux/mm.h:449 [inline]
 [<ffffffff8144bce1>] __free_pages+0x21/0x80 mm/page_alloc.c:3901
RSP: 0018:ffff8801c6acfab0  EFLAGS: 00010a07
RAX: dffffc0000000000 RBX: dead4ead00000000 RCX: ffffc900002b8000
RDX: 1bd5a9d5a0000003 RSI: 0000000000000001 RDI: dead4ead0000001c
RBP: ffff8801c6acfac0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000004
R13: 0000000000000020 R14: ffff8801ad700000 R15: dffffc0000000000
FS:  00007f81cc895700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020486000 CR3: 00000001d9bdf000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d8860000
 ffff8801ad700158 ffff8801c6acfb20 ffffffff8265f591[  177.474738]  ffff8801ad700170
 ffffed0035ae002b ffffed0035ae002e ffff8801ad700168[  177.474754]  dead4ead00000000
 ffff8801ad700140 0000000000000000 0000000000000000[  177.474763] Call Trace:
 [<ffffffff8265f591>] sg_remove_scat.isra.20+0x1c1/0x2d0 drivers/scsi/sg.c:1954
 [<ffffffff8265f955>] sg_finish_rem_req+0x2b5/0x340 drivers/scsi/sg.c:1836
 [<ffffffff8265fa19>] sg_new_read.isra.21+0x39/0x3e0 drivers/scsi/sg.c:567
 [<ffffffff8266160d>] sg_read+0x8bd/0x1440 drivers/scsi/sg.c:456
 [<ffffffff81568193>] __vfs_read+0x103/0x670 fs/read_write.c:452
 [<ffffffff8156bf2e>] vfs_read+0x11e/0x380 fs/read_write.c:475
 [<ffffffff8156fc59>] SYSC_read fs/read_write.c:591 [inline]
 [<ffffffff8156fc59>] SyS_read+0xd9/0x1b0 fs/read_write.c:584
 [<ffffffff838a9785>] 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 [  177.475107] RIP 
 [<ffffffff8144bce1>] __read_once_size include/linux/compiler.h:243 [inline]
 [<ffffffff8144bce1>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
 [<ffffffff8144bce1>] page_ref_count include/linux/page_ref.h:66 [inline]
 [<ffffffff8144bce1>] put_page_testzero include/linux/mm.h:449 [inline]
 [<ffffffff8144bce1>] __free_pages+0x21/0x80 mm/page_alloc.c:3901
---[ end trace eb66c42aaee704aa ]---
Kernel panic - not syncing: Fatal exception
 0000000000002871 ffff8801aa1be8f0 ffff8801aa1be8a0
 [<ffffffff81d90429>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d90429>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8165e3c7>] handle_userfault+0xa37/0x1300 fs/userfaultfd.c:323
 [<ffffffff814cd6c1>] do_anonymous_page mm/memory.c:2747 [inline]
 [<ffffffff814cd6c1>] handle_pte_fault mm/memory.c:3488 [inline]
 [<ffffffff814cd6c1>] __handle_mm_fault mm/memory.c:3577 [inline]
 [<ffffffff814cd6c1>] handle_mm_fault+0x1fd1/0x2530 mm/memory.c:3614
 [<ffffffff810dd447>] __do_page_fault+0x5b7/0xd70 arch/x86/mm/fault.c:1396
 [<ffffffff810ddc27>] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1460
 [<ffffffff838aa958>] page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1012
 [<ffffffff838a9785>] entry_SYSCALL_64_fastpath+0x23/0xc6
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..