================================================================== BUG: KCSAN: data-race in ondemand_readahead / ondemand_readahead write to 0xffff8881216768a0 of 4 bytes by task 6214 on cpu 1: ondemand_readahead+0x2ab/0x6e0 mm/readahead.c:530 page_cache_sync_readahead+0x178/0x1a0 mm/readahead.c:585 generic_file_buffered_read+0x2ec/0x1f60 mm/filemap.c:2101 generic_file_read_iter+0x7d/0x3e0 mm/filemap.c:2405 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 0xffff8881216768a0 of 4 bytes by task 6203 on cpu 0: ondemand_readahead+0x136/0x6e0 mm/readahead.c:467 page_cache_sync_readahead+0x178/0x1a0 mm/readahead.c:585 generic_file_buffered_read+0x2ec/0x1f60 mm/filemap.c:2101 generic_file_read_iter+0x7d/0x3e0 mm/filemap.c:2405 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 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 6203 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================