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BUG: KCSAN: data-race in __filemap_add_folio / file_write_and_wait_range

read-write to 0xffff8881381f64e0 of 8 bytes by task 712 on cpu 1:
 __filemap_add_folio+0x38c/0x720 mm/filemap.c:904
 filemap_add_folio+0x6f/0x150 mm/filemap.c:939
 page_cache_ra_unbounded+0x15e/0x2e0 mm/readahead.c:251
 do_page_cache_ra mm/readahead.c:300 [inline]
 page_cache_ra_order mm/readahead.c:560 [inline]
 ondemand_readahead+0x550/0x6c0 mm/readahead.c:682
 page_cache_async_ra+0x9d/0xb0 mm/readahead.c:731
 filemap_readahead mm/filemap.c:2573 [inline]
 filemap_get_pages+0x38c/0xea0 mm/filemap.c:2614
 filemap_read+0x223/0x680 mm/filemap.c:2693
 generic_file_read_iter+0x76/0x320 mm/filemap.c:2840
 ext4_file_read_iter+0x1cc/0x290
 call_read_iter include/linux/fs.h:1845 [inline]
 generic_file_splice_read+0xe3/0x290 fs/splice.c:402
 do_splice_to fs/splice.c:885 [inline]
 splice_direct_to_actor+0x25a/0x5f0 fs/splice.c:956
 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 0xffff8881381f64e0 of 8 bytes by task 724 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: 0x000000000000014e -> 0x0000000000000151

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 724 Comm: syz-executor.5 Not tainted 6.3.0-rc7-syzkaller-00181-g8e41e0a57566 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
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