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BUG: KCSAN: data-race in __filemap_add_folio / file_write_and_wait_range

read-write to 0xffff8881251a3830 of 8 bytes by task 20355 on cpu 1:
 __filemap_add_folio+0x4e9/0x990 mm/filemap.c:898
 filemap_add_folio+0x6b/0x150 mm/filemap.c:933
 page_cache_ra_unbounded+0x19e/0x2e0 mm/readahead.c:245
 do_page_cache_ra mm/readahead.c:293 [inline]
 page_cache_ra_order mm/readahead.c:550 [inline]
 ondemand_readahead+0x5df/0x780 mm/readahead.c:672
 page_cache_sync_ra+0xdc/0xf0 mm/readahead.c:699
 page_cache_sync_readahead include/linux/pagemap.h:1215 [inline]
 filemap_get_pages mm/filemap.c:2566 [inline]
 filemap_read+0x3ef/0x1430 mm/filemap.c:2660
 generic_file_read_iter+0x72/0x320 mm/filemap.c:2806
 ext4_file_read_iter+0x1e9/0x2a0
 call_read_iter include/linux/fs.h:2181 [inline]
 generic_file_splice_read+0xde/0x2b0 fs/splice.c:309
 do_splice_to fs/splice.c:793 [inline]
 splice_direct_to_actor+0x26c/0x620 fs/splice.c:865
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881251a3830 of 8 bytes by task 20376 on cpu 0:
 mapping_needs_writeback mm/filemap.c:627 [inline]
 file_write_and_wait_range+0x4b/0x170 mm/filemap.c:772
 ext4_sync_file+0x105/0x6d0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2869 [inline]
 iomap_dio_complete+0x3e7/0x460 fs/iomap/direct-io.c:128
 iomap_dio_rw+0x5e/0x80 fs/iomap/direct-io.c:694
 ext4_dio_write_iter fs/ext4/file.c:566 [inline]
 ext4_file_write_iter+0xaa9/0x1210 fs/ext4/file.c:677
 do_iter_write+0x494/0x750 fs/read_write.c:855
 vfs_iter_write+0x4c/0x70 fs/read_write.c:896
 iter_file_splice_write+0x44a/0x7c0 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:931
 splice_direct_to_actor+0x305/0x620 fs/splice.c:886
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000287 -> 0x0000000000000288

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 20376 Comm: syz-executor.4 Not tainted 6.0.0-rc5-syzkaller-00097-g38eddeedbbea-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
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