Not allocated shadow for addr ffff8801a3940000 (page ffffea0009d57800)
Attempted to access 4096 bytes
------------[ cut here ]------------
kernel BUG at mm/kmsan/kmsan.c:1326!
invalid opcode: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4495 Comm: syz-executor024 Not tainted 4.16.0+ #87
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:1325
RSP: 0018:ffff8801bdbdf2b8 EFLAGS: 00010082
RAX: 000000000000001e RBX: 0000000000000680 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000000
RBP: ffff8801bdbdf2d0 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801a3940000
R13: 0000000000004000 R14: 0000000000000001 R15: 0000000000001000
FS:  00007f7f9bfd0700(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020006000 CR3: 000000019feac000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kmsan_internal_memset_shadow mm/kmsan/kmsan.c:171 [inline]
 kmsan_internal_unpoison_shadow+0x5c/0xe0 mm/kmsan/kmsan.c:208
 kmsan_unpoison_shadow+0x66/0xb0 mm/kmsan/kmsan.c:222
 get_user_pages_fast+0x47b/0x760 mm/gup.c:1823
 iov_iter_get_pages+0x465/0x1810 lib/iov_iter.c:1074
 dio_refill_pages fs/direct-io.c:170 [inline]
 dio_get_page fs/direct-io.c:214 [inline]
 do_direct_IO fs/direct-io.c:981 [inline]
 do_blockdev_direct_IO fs/direct-io.c:1335 [inline]
 __blockdev_direct_IO+0x1b51/0x66d0 fs/direct-io.c:1421
 ext4_direct_IO_read fs/ext4/inode.c:3830 [inline]
 ext4_direct_IO+0xd51/0x2410 fs/ext4/inode.c:3866
 generic_file_read_iter+0x3bd2/0x4440 mm/filemap.c:2343
 ext4_file_read_iter+0x30f/0x520 include/linux/fs.h:728
 call_read_iter include/linux/fs.h:1776 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x7dd/0x9b0 fs/read_write.c:413
 vfs_read+0x36c/0x6c0 fs/read_write.c:447
 SYSC_read+0x172/0x360 fs/read_write.c:573
 SyS_read+0x55/0x80 fs/read_write.c:566
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x446769
RSP: 002b:00007f7f9bfcfce8 EFLAGS: 00000206 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000000006dbcac RCX: 0000000000446769
RDX: 0000000000008000 RSI: 0000000020000200 RDI: 0000000000000010
RBP: 00000000006dbca8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ffdae5e0d7f R14: 00007f7f9bfd09c0 R15: 0000000000000001
Code: 75 29 48 c7 c7 fd 92 7d 8a 31 c0 e8 4d 68 86 ff 80 3c 25 e8 03 2c 8b 00 75 11 48 c7 c7 2d 93 7d 8a 31 c0 4c 89 fe e8 32 68 86 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:1325 RSP: ffff8801bdbdf2b8
---[ end trace 20db1598a544f1f5 ]---