==================================================================
BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:140 [inline]
BUG: KMSAN: kernel-infoleak in copy_page_to_iter_iovec lib/iov_iter.c:212 [inline]
BUG: KMSAN: kernel-infoleak in copy_page_to_iter+0x754/0x1b70 lib/iov_iter.c:716
CPU: 1 PID: 12503 Comm: syz-executor3 Not tainted 4.17.0+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1125
 kmsan_internal_check_memory+0x17e/0x1f0 mm/kmsan/kmsan.c:1238
 kmsan_copy_to_user+0x7a/0x160 mm/kmsan/kmsan.c:1261
 copyout lib/iov_iter.c:140 [inline]
 copy_page_to_iter_iovec lib/iov_iter.c:212 [inline]
 copy_page_to_iter+0x754/0x1b70 lib/iov_iter.c:716
 generic_file_buffered_read mm/filemap.c:2185 [inline]
 generic_file_read_iter+0x2ef8/0x44d0 mm/filemap.c:2362
 call_read_iter include/linux/fs.h:1778 [inline]
 new_sync_read fs/read_write.c:406 [inline]
 __vfs_read+0x775/0x9d0 fs/read_write.c:418
 vfs_read+0x36c/0x6b0 fs/read_write.c:452
 ksys_read fs/read_write.c:578 [inline]
 __do_sys_read fs/read_write.c:588 [inline]
 __se_sys_read fs/read_write.c:586 [inline]
 __x64_sys_read+0x1bf/0x3e0 fs/read_write.c:586
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455a99
RSP: 002b:00007ff8d8bccc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007ff8d8bcd6d4 RCX: 0000000000455a99
RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c07ef R14: 00000000004d0338 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:282 [inline]
 kmsan_alloc_meta_for_pages+0x161/0x3a0 mm/kmsan/kmsan.c:819
 kmsan_alloc_page+0x82/0xe0 mm/kmsan/kmsan.c:889
 __alloc_pages_nodemask+0xf7b/0x5cc0 mm/page_alloc.c:4402
 alloc_pages_current+0x6b1/0x970 mm/mempolicy.c:2093
 alloc_pages include/linux/gfp.h:494 [inline]
 __page_cache_alloc+0x95/0x320 mm/filemap.c:946
 page_cache_read mm/filemap.c:2385 [inline]
 filemap_fault+0x15eb/0x2590 mm/filemap.c:2569
 __do_fault mm/memory.c:3224 [inline]
 do_read_fault mm/memory.c:3634 [inline]
 do_fault mm/memory.c:3734 [inline]
 handle_pte_fault mm/memory.c:3965 [inline]
 __handle_mm_fault mm/memory.c:4089 [inline]
 handle_mm_fault+0x61a1/0x7ed0 mm/memory.c:4126
 __do_page_fault+0xec6/0x1a10 arch/x86/mm/fault.c:1400
x_tables: eb_tables: snat target: used from hooks PREROUTING, but only usable from POSTROUTING
 do_page_fault+0xb7/0x250 arch/x86/mm/fault.c:1477
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1163
 copy_user_enhanced_fast_string+0xe/0x20 arch/x86/lib/copy_user_64.S:180
 copy_from_user include/linux/uaccess.h:171 [inline]
 rw_copy_check_uvector+0x24c/0x6c0 fs/read_write.c:787
 import_iovec+0x18f/0x600 lib/iov_iter.c:1404
 vfs_readv fs/read_write.c:984 [inline]
 do_readv+0x21c/0x5f0 fs/read_write.c:1019
 __do_sys_readv fs/read_write.c:1106 [inline]
 __se_sys_readv fs/read_write.c:1103 [inline]
 __x64_sys_readv+0xe1/0x120 fs/read_write.c:1103
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Bytes 0-7 of 8 are uninitialized
Memory access starts at ffff8801ab810000
==================================================================