================================================================== BUG: KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages write to 0xffff88811ecd2700 of 8 bytes by task 10107 on cpu 1: __add_to_page_cache_locked+0x2cc/0x6e0 mm/filemap.c:867 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:918 generic_file_buffered_read+0xbed/0x1800 mm/filemap.c:2219 generic_file_read_iter+0x7d/0x3e0 mm/filemap.c:2307 ext4_file_read_iter+0x2d6/0x420 fs/ext4/file.c:74 call_read_iter include/linux/fs.h:1901 [inline] generic_file_splice_read+0x22a/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+0x562/0xb10 fs/read_write.c:1521 __do_sys_sendfile64 fs/read_write.c:1582 [inline] __se_sys_sendfile64 fs/read_write.c:1568 [inline] __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1568 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff88811ecd2700 of 8 bytes by task 10117 on cpu 0: ext4_writepages+0x145/0x1ef0 fs/ext4/inode.c:2650 do_writepages+0x7b/0x150 mm/page-writeback.c:2354 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:421 filemap_write_and_wait_range+0x8b/0x2a0 mm/filemap.c:654 iomap_dio_rw+0x399/0x8c0 fs/iomap/direct-io.c:474 ext4_dio_read_iter fs/ext4/file.c:77 [inline] ext4_file_read_iter+0x3bc/0x420 fs/ext4/file.c:129 call_read_iter include/linux/fs.h:1901 [inline] generic_file_splice_read+0x22a/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+0x562/0xb10 fs/read_write.c:1521 __do_sys_sendfile64 fs/read_write.c:1582 [inline] __se_sys_sendfile64 fs/read_write.c:1568 [inline] __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1568 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 10117 Comm: syz-executor.3 Not tainted 5.8.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================