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BUG: KCSAN: data-race in copy_page_to_iter / fat_set_state

write to 0xffff888137bf1025 of 1 bytes by task 24289 on cpu 1:
 fat_set_state+0x16c/0x1d0 fs/fat/inode.c:705
 fat_fill_super+0x263a/0x2a80 fs/fat/inode.c:1885
 msdos_fill_super+0x29/0x30 fs/fat/namei_msdos.c:655
 mount_bdev+0x1e8/0x290 fs/super.c:1368
 msdos_mount+0x2d/0x40 fs/fat/namei_msdos.c:662
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1498
 do_new_mount fs/namespace.c:2987 [inline]
 path_mount+0x11ca/0x1d00 fs/namespace.c:3317
 do_mount fs/namespace.c:3330 [inline]
 __do_sys_mount fs/namespace.c:3538 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3515
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3515
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888137bf1000 of 1377 bytes by task 24294 on cpu 0:
 instrument_copy_to_user include/linux/instrumented.h:119 [inline]
 copyout lib/iov_iter.c:156 [inline]
 copy_page_to_iter_iovec lib/iov_iter.c:228 [inline]
 __copy_page_to_iter lib/iov_iter.c:801 [inline]
 copy_page_to_iter+0x2e1/0x940 lib/iov_iter.c:829
 filemap_read+0xed6/0x1210 mm/filemap.c:2686
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2782
 blkdev_read_iter+0xb9/0xf0 fs/block_dev.c:1488
 call_read_iter include/linux/fs.h:2157 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x651/0x730 fs/read_write.c:485
 ksys_read+0xce/0x180 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:631
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24294 Comm: systemd-udevd Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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