================================================================== BUG: KCSAN: data-race in ondemand_readahead / ondemand_readahead write to 0xffff8881212152a4 of 4 bytes by task 13549 on cpu 1: ondemand_readahead+0x439/0x710 mm/readahead.c:472 page_cache_sync_readahead+0x1ad/0x1e0 mm/readahead.c:527 generic_file_buffered_read mm/filemap.c:2051 [inline] generic_file_read_iter+0xeb6/0x1440 mm/filemap.c:2324 ext4_file_read_iter fs/ext4/file.c:77 [inline] ext4_file_read_iter+0xfa/0x240 fs/ext4/file.c:65 call_read_iter include/linux/fs.h:1889 [inline] generic_file_splice_read+0x35c/0x500 fs/splice.c:307 do_splice_to+0xf2/0x130 fs/splice.c:877 splice_direct_to_actor+0x1a1/0x510 fs/splice.c:954 do_splice_direct+0x161/0x1e0 fs/splice.c:1063 do_sendfile+0x384/0x7f0 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x12a/0x140 fs/read_write.c:1511 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8881212152a4 of 4 bytes by task 13555 on cpu 0: ondemand_readahead+0x127/0x710 mm/readahead.c:409 page_cache_sync_readahead+0x1ad/0x1e0 mm/readahead.c:527 generic_file_buffered_read mm/filemap.c:2051 [inline] generic_file_read_iter+0xeb6/0x1440 mm/filemap.c:2324 ext4_file_read_iter fs/ext4/file.c:77 [inline] ext4_file_read_iter+0xfa/0x240 fs/ext4/file.c:65 call_read_iter include/linux/fs.h:1889 [inline] generic_file_splice_read+0x35c/0x500 fs/splice.c:307 do_splice_to+0xf2/0x130 fs/splice.c:877 splice_direct_to_actor+0x1a1/0x510 fs/splice.c:954 do_splice_direct+0x161/0x1e0 fs/splice.c:1063 do_sendfile+0x384/0x7f0 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x12a/0x140 fs/read_write.c:1511 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 13555 Comm: syz-executor.5 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================