================================================================== BUG: KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages read-write to 0xffff88810d1004d8 of 8 bytes by task 23452 on cpu 1: __add_to_page_cache_locked+0x3a2/0x6b0 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_sync_ra+0x1ab/0x1c0 mm/readahead.c:577 page_cache_sync_readahead include/linux/pagemap.h:839 [inline] generic_file_buffered_read_get_pages+0x234/0xaf0 mm/filemap.c:2361 generic_file_buffered_read+0x27f/0x9a0 mm/filemap.c:2481 generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2633 ext4_file_read_iter+0x2d0/0x420 fs/ext4/file.c:74 call_read_iter include/linux/fs.h:1895 [inline] generic_file_splice_read+0x22a/0x310 fs/splice.c:311 do_splice_to fs/splice.c:788 [inline] splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867 do_splice_direct+0xf5/0x170 fs/splice.c:976 do_sendfile+0x5db/0xca0 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 read to 0xffff88810d1004d8 of 8 bytes by task 23456 on cpu 0: ext4_writepages+0x131/0x1e30 fs/ext4/inode.c:2660 do_writepages+0x7b/0x150 mm/page-writeback.c:2352 __filemap_fdatawrite_range+0x19d/0x1d0 mm/filemap.c:422 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:761 ext4_sync_file+0x105/0x6c0 fs/ext4/fsync.c:151 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2737 [inline] ext4_buffered_write_iter+0x384/0x3d0 fs/ext4/file.c:278 ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503 call_write_iter include/linux/fs.h:1901 [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+0x5db/0xca0 fs/read_write.c:1257 __do_sys_sendfile64 fs/read_write.c:1312 [inline] __se_sys_sendfile64 fs/read_write.c:1304 [inline] __x64_sys_sendfile64+0xa9/0x130 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: 23456 Comm: syz-executor.1 Not tainted 5.10.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================