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BUG: KCSAN: data-race in __add_to_page_cache_locked / dio_complete

write to 0xffff88813602d388 of 8 bytes by task 13063 on cpu 0:
 __add_to_page_cache_locked+0x256/0x4b0 mm/filemap.c:914
 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:967
 page_cache_ra_unbounded+0x262/0x410 mm/readahead.c:221
 ondemand_readahead+0x579/0x7b0 mm/readahead.c:267
 page_cache_sync_ra+0xaf/0xe0 mm/readahead.c:578
 page_cache_sync_readahead include/linux/pagemap.h:884 [inline]
 filemap_get_pages mm/filemap.c:2467 [inline]
 filemap_read+0x388/0x1220 mm/filemap.c:2550
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701
 call_read_iter include/linux/fs.h:2108 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 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 0xffff88813602d388 of 8 bytes by task 13060 on cpu 1:
 dio_complete+0x238/0x480 fs/direct-io.c:291
 do_blockdev_direct_IO fs/direct-io.c:1336 [inline]
 __blockdev_direct_IO+0x23e3/0x2500 fs/direct-io.c:1368
 blockdev_direct_IO include/linux/fs.h:3303 [inline]
 fat_direct_IO+0x111/0x1e0 fs/fat/inode.c:288
 generic_file_direct_write+0x27d/0x4f0 mm/filemap.c:3558
 __generic_file_write_iter+0x1a9/0x300 mm/filemap.c:3740
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3815
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 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

value changed: 0x0000000000000089 -> 0x000000000000008a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13060 Comm: syz-executor.1 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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