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BUG: KCSAN: data-race in __filemap_add_folio / file_write_and_wait_range

read-write to 0xffff88810af7c930 of 8 bytes by task 6743 on cpu 1:
 __filemap_add_folio+0x38c/0x720 mm/filemap.c:904
 filemap_add_folio+0x6f/0x150 mm/filemap.c:939
 __filemap_get_folio+0x554/0x750 mm/filemap.c:1981
 pagecache_get_page+0x2a/0xd0 mm/folio-compat.c:99
 grab_cache_page_write_begin+0x2e/0x40 mm/folio-compat.c:111
 ext4_da_write_begin+0x2ce/0x610 fs/ext4/inode.c:3073
 generic_perform_write+0x1c3/0x3d0 mm/filemap.c:3926
 ext4_buffered_write_iter+0x234/0x3e0 fs/ext4/file.c:289
 ext4_file_write_iter+0xd7/0x10e0
 do_iter_write+0x418/0x700 fs/read_write.c:861
 vfs_iter_write+0x50/0x70 fs/read_write.c:902
 iter_file_splice_write+0x456/0x7d0 fs/splice.c:778
 do_splice_from fs/splice.c:856 [inline]
 direct_splice_actor+0x84/0xa0 fs/splice.c:1022
 splice_direct_to_actor+0x2ee/0x5f0 fs/splice.c:977
 do_splice_direct+0x104/0x180 fs/splice.c:1065
 do_sendfile+0x3b8/0x950 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810af7c930 of 8 bytes by task 6744 on cpu 0:
 mapping_needs_writeback mm/filemap.c:628 [inline]
 file_write_and_wait_range+0x6a/0x190 mm/filemap.c:780
 ext4_sync_file+0x10d/0x720 fs/ext4/fsync.c:151
 vfs_fsync_range+0x10b/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2452 [inline]
 ext4_buffered_write_iter+0x397/0x3e0 fs/ext4/file.c:296
 ext4_file_write_iter+0xd7/0x10e0
 do_iter_write+0x418/0x700 fs/read_write.c:861
 vfs_iter_write+0x50/0x70 fs/read_write.c:902
 iter_file_splice_write+0x456/0x7d0 fs/splice.c:778
 do_splice_from fs/splice.c:856 [inline]
 direct_splice_actor+0x84/0xa0 fs/splice.c:1022
 splice_direct_to_actor+0x2ee/0x5f0 fs/splice.c:977
 do_splice_direct+0x104/0x180 fs/splice.c:1065
 do_sendfile+0x3b8/0x950 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000000018f1 -> 0x00000000000018f2

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6744 Comm: syz-executor.3 Not tainted 6.3.0-rc3-syzkaller-00317-g65aca32efdcb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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