================================================================== BUG: KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages write to 0xffff8881206fc400 of 8 bytes by task 1303 on cpu 1: __add_to_page_cache_locked+0x2cc/0x710 mm/filemap.c:868 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:919 page_cache_readahead_unbounded+0x234/0x470 mm/readahead.c:228 ondemand_readahead+0x4e4/0x6e0 mm/readahead.c:273 page_cache_sync_readahead+0x178/0x1a0 mm/readahead.c:585 generic_file_buffered_read+0x2ec/0x1f60 mm/filemap.c:2199 generic_file_read_iter+0x7d/0x3e0 mm/filemap.c:2503 ext4_file_read_iter+0x2d8/0x420 fs/ext4/file.c:74 call_read_iter include/linux/fs.h:1876 [inline] generic_file_splice_read+0x22b/0x310 fs/splice.c:312 do_splice_to fs/splice.c:870 [inline] splice_direct_to_actor+0x2a8/0x660 fs/splice.c:950 do_splice_direct+0xf2/0x170 fs/splice.c:1059 do_sendfile+0x56a/0xba0 fs/read_write.c:1540 __do_sys_sendfile64 fs/read_write.c:1601 [inline] __se_sys_sendfile64 fs/read_write.c:1587 [inline] __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8881206fc400 of 8 bytes by task 1314 on cpu 0: ext4_writepages+0x145/0x1ef0 fs/ext4/inode.c:2649 do_writepages+0x7b/0x150 mm/page-writeback.c:2352 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:422 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:761 ext4_sync_file+0xfc/0x6e0 fs/ext4/fsync.c:151 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2747 [inline] ext4_buffered_write_iter+0x369/0x3b0 fs/ext4/file.c:276 ext4_file_write_iter+0x768/0x1060 include/linux/fs.h:784 call_write_iter include/linux/fs.h:1882 [inline] do_iter_readv_writev+0x32e/0x3d0 fs/read_write.c:713 do_iter_write+0x112/0x4b0 fs/read_write.c:1018 vfs_iter_write+0x4c/0x70 fs/read_write.c:1059 iter_file_splice_write+0x41a/0x770 fs/splice.c:750 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x95/0x160 fs/splice.c:1016 splice_direct_to_actor+0x365/0x660 fs/splice.c:971 do_splice_direct+0xf2/0x170 fs/splice.c:1059 do_sendfile+0x56a/0xba0 fs/read_write.c:1540 __do_sys_sendfile64 fs/read_write.c:1601 [inline] __se_sys_sendfile64 fs/read_write.c:1587 [inline] __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587 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: 1314 Comm: syz-executor.4 Not tainted 5.9.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================