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BUG: KCSAN: data-race in __writeback_single_inode / xas_set_mark

write to 0xffff88810ae1255c of 4 bytes by task 7326 on cpu 0:
 xas_set_mark+0x131/0x140
 tag_pages_for_writeback+0xaa/0x2a0
 write_cache_pages+0x192/0xaa0
 mpage_writepages+0x72/0xe0
 fat_writepages+0x24/0x30
 do_writepages+0x1c7/0x330
 filemap_fdatawrite_wbc+0xdb/0xf0
 file_write_and_wait_range+0xfa/0x190
 __generic_file_fsync+0x4c/0x140
 fat_file_fsync+0x4c/0x100
 vfs_fsync_range+0x10b/0x120
 generic_file_write_iter+0x191/0x1c0
 do_iter_write+0x418/0x700
 vfs_iter_write+0x50/0x70
 iter_file_splice_write+0x42b/0x7b0
 direct_splice_actor+0x84/0xa0
 splice_direct_to_actor+0x2ee/0x5f0
 do_splice_direct+0x104/0x180
 do_sendfile+0x3b8/0x950
 __x64_sys_sendfile64+0x110/0x150
 do_syscall_64+0x41/0xc0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810ae1255c of 4 bytes by task 7308 on cpu 1:
 __writeback_single_inode+0x21d/0x860
 writeback_single_inode+0x12f/0x4a0
 sync_inode_metadata+0x56/0x80
 __generic_file_fsync+0xf9/0x140
 fat_file_fsync+0x4c/0x100
 vfs_fsync_range+0x10b/0x120
 generic_file_write_iter+0x191/0x1c0
 do_iter_write+0x418/0x700
 vfs_iter_write+0x50/0x70
 iter_file_splice_write+0x42b/0x7b0
 direct_splice_actor+0x84/0xa0
 splice_direct_to_actor+0x2ee/0x5f0
 do_splice_direct+0x104/0x180
 do_sendfile+0x3b8/0x950
 __x64_sys_sendfile64+0x110/0x150
 do_syscall_64+0x41/0xc0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x08000021 -> 0x10000021

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7308 Comm: syz-executor.0 Not tainted 6.2.0-rc6-syzkaller-00258-gdb27c22251e7-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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