Not allocated shadow for addr ffff8800af400000 (page ffffea00041b8000)
Attempted to access 4096 bytes
------------[ cut here ]------------
kernel BUG at mm/kmsan/kmsan.c:1378!
invalid opcode: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 14027 Comm: syz-executor0 Not tainted 4.17.0+ #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kmsan_get_shadow_address+0x1ce/0x1f0 mm/kmsan/kmsan.c:1377
RSP: 0018:ffff880170edf360 EFLAGS: 00010082
RAX: 000000000000001e RBX: 00000000000002a0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000bc45 RDI: 000000000000bc46
RBP: ffff880170edf378 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: ffffffff865757b0 R12: ffff8800af400000
R13: 0000000000002000 R14: 0000000000000001 R15: 0000000000001000
FS:  00007f5876a94700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000701138 CR3: 000000016fba0000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 kmsan_internal_memset_shadow mm/kmsan/kmsan.c:172 [inline]
 kmsan_internal_unpoison_shadow+0x5c/0xe0 mm/kmsan/kmsan.c:209
 kmsan_unpoison_shadow+0x66/0xb0 mm/kmsan/kmsan.c:223
 get_user_pages_fast+0x493/0x770 mm/gup.c:1831
 iov_iter_get_pages+0x465/0x1810 lib/iov_iter.c:1074
 bio_iov_iter_get_pages+0x1c6/0xc70 block/bio.c:891
 __blkdev_direct_IO fs/block_dev.c:359 [inline]
 blkdev_direct_IO+0x1252/0x2d90 fs/block_dev.c:430
 generic_file_read_iter+0x3c6d/0x44d0 mm/filemap.c:2341
 blkdev_read_iter+0x20d/0x280 fs/block_dev.c:1930
 do_iter_readv_writev+0x81c/0xa20 include/linux/fs.h:1778
 do_iter_read+0x303/0xd80 fs/read_write.c:922
 vfs_readv fs/read_write.c:986 [inline]
 do_preadv+0x3a1/0x580 fs/read_write.c:1070
 __do_sys_preadv fs/read_write.c:1120 [inline]
 __se_sys_preadv fs/read_write.c:1115 [inline]
 __x64_sys_preadv+0x120/0x170 fs/read_write.c:1115
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455b29
RSP: 002b:00007f5876a93c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007f5876a946d4 RCX: 0000000000455b29
RDX: 0000000000000001 RSI: 0000000020000040 RDI: 0000000000000014
RBP: 000000000072bf50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c068f R14: 00000000004cfc40 R15: 0000000000000001
Code: 75 29 48 c7 c7 59 38 97 8a 31 c0 e8 fd 4c 80 ff 80 3c 25 f8 93 53 8b 00 75 11 48 c7 c7 89 38 97 8a 31 c0 4c 89 fe e8 e2 4c 80 ff <0f> 0b eb fe 48 3d ff ff ff 1f 0f 87 a2 fe ff ff 48 8b 1c 25 10 
RIP: kmsan_get_shadow_address+0x1ce/0x1f0 mm/kmsan/kmsan.c:1377 RSP: ffff880170edf360
---[ end trace 09f1a8ffe79649ca ]---