syzbot

File: /root/syzkaller-testdir584301003/syzkaller.ymifod/144/bus PID: 15740 Comm: syz-executor.4
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BUG: KCSAN: data-race in __add_to_page_cache_locked / iomap_dio_complete

read-write to 0xffff88810d7b1878 of 8 bytes by task 15749 on cpu 1:
 __add_to_page_cache_locked+0x39d/0x7b0 mm/filemap.c:888
 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:939
 page_cache_ra_unbounded+0x272/0x4c0 mm/readahead.c:222
 ondemand_readahead+0x560/0x780 mm/readahead.c:267
 page_cache_async_ra+0x1aa/0x1d0 mm/readahead.c:607
 page_cache_async_readahead include/linux/pagemap.h:862 [inline]
 generic_file_buffered_read+0x455/0x2110 mm/filemap.c:2239
 generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2535
 ext4_file_read_iter+0x2d0/0x420 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1881 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x552/0x5c0 fs/read_write.c:496
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d7b1878 of 8 bytes by task 15740 on cpu 0:
 iomap_dio_complete+0x306/0x3a0 fs/iomap/direct-io.c:112
 iomap_dio_rw+0x4e/0x70 fs/iomap/direct-io.c:608
 ext4_dio_write_iter fs/ext4/file.c:552 [inline]
 ext4_file_write_iter+0xe06/0x1090 fs/ext4/file.c:662
 call_write_iter include/linux/fs.h:1887 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4b0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x42a/0x780 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:933
 splice_direct_to_actor+0x345/0x650 fs/splice.c:888
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x574/0xb70 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15740 Comm: syz-executor.4 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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