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BUG: KMSAN: kernel-infoleak in copyout+0x16b/0x1f0 lib/iov_iter.c:144
CPU: 1 PID: 10345 Comm: blkid Not tainted 5.0.0-rc1+ #7
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+0x173/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:600
 kmsan_internal_check_memory+0x9e4/0xb10 mm/kmsan/kmsan.c:692
 kmsan_copy_to_user+0xab/0xc0 mm/kmsan/kmsan_hooks.c:601
 copyout+0x16b/0x1f0 lib/iov_iter.c:144
 copy_page_to_iter_iovec lib/iov_iter.c:216 [inline]
 copy_page_to_iter+0x654/0x17e0 lib/iov_iter.c:892
 generic_file_buffered_read mm/filemap.c:2174 [inline]
 generic_file_read_iter+0x2f2c/0x4620 mm/filemap.c:2351
 blkdev_read_iter+0x20d/0x270 fs/block_dev.c:1959
 call_read_iter include/linux/fs.h:1856 [inline]
 new_sync_read fs/read_write.c:406 [inline]
 __vfs_read+0x94e/0xbf0 fs/read_write.c:418
 vfs_read+0x359/0x6f0 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+0x17a/0x370 fs/read_write.c:586
 __x64_sys_read+0x4a/0x70 fs/read_write.c:586
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x7f73fc0b0310
Code: 73 01 c3 48 8b 0d 28 4b 2b 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 83 3d e5 a2 2b 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 6e 8a 01 00 48 89 04 24
RSP: 002b:00007ffdcc737148 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f73fc0b0310
RDX: 0000000000000100 RSI: 0000000002348df8 RDI: 0000000000000003
RBP: 0000000002348dd0 R08: 0000000000000028 R09: 0000000001680000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000002348030
R13: 0000000000000100 R14: 0000000002348080 R15: 0000000002348de8

Uninit was created at:
 kmsan_save_stack_with_flags+0x7a/0x130 mm/kmsan/kmsan.c:205
 kmsan_internal_alloc_meta_for_pages+0x113/0x580 mm/kmsan/kmsan_hooks.c:98
 kmsan_alloc_page+0x7e/0x100 mm/kmsan/kmsan_hooks.c:396
 __alloc_pages_nodemask+0x137b/0x5e30 mm/page_alloc.c:4572
 alloc_pages_current+0x69d/0x9b0 mm/mempolicy.c:2106
 alloc_pages include/linux/gfp.h:511 [inline]
 __page_cache_alloc+0x95/0x320 mm/filemap.c:925
 pagecache_get_page+0x4f4/0x1300 mm/filemap.c:1616
 grab_cache_page_write_begin+0x100/0x180 mm/filemap.c:3161
 block_write_begin+0x102/0x3c0 fs/buffer.c:2076
 blkdev_write_begin+0xf5/0x110 fs/block_dev.c:608
 generic_perform_write+0x412/0x990 mm/filemap.c:3211
 __generic_file_write_iter+0x422/0xa30 mm/filemap.c:3336
 blkdev_write_iter+0x3f0/0x650 fs/block_dev.c:1939
 call_write_iter include/linux/fs.h:1862 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x98a/0xc20 fs/read_write.c:487
 vfs_write+0x481/0x920 fs/read_write.c:549
 ksys_write fs/read_write.c:598 [inline]
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write+0x17a/0x370 fs/read_write.c:607
 __x64_sys_write+0x4a/0x70 fs/read_write.c:607
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Bytes 8-255 of 256 are uninitialized
Memory access of size 256 starts at ffff8880a7e58000
Data copied to user address 0000000002348df8
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