================================================================== BUG: KCSAN: data-race in ext4_sync_file / writeback_single_inode write to 0xffff8880b7105280 of 8 bytes by task 18376 on cpu 0: inode_sync_complete fs/fs-writeback.c:1197 [inline] writeback_single_inode+0x39e/0x520 fs/fs-writeback.c:1578 sync_inode fs/fs-writeback.c:2602 [inline] sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2622 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline] ext4_sync_file+0x30c/0x680 fs/ext4/fsync.c:170 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2882 [inline] ext4_buffered_write_iter+0x34e/0x390 fs/ext4/file.c:277 ext4_file_write_iter+0x4a3/0xfd0 fs/ext4/file.c:498 call_write_iter include/linux/fs.h:1907 [inline] do_iter_readv_writev+0x321/0x3c0 fs/read_write.c:694 do_iter_write+0x10e/0x470 fs/read_write.c:999 vfs_iter_write+0x4c/0x70 fs/read_write.c:1040 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+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+0x71/0x120 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8880b7105280 of 8 bytes by task 18363 on cpu 1: ext4_fsync_nojournal fs/ext4/fsync.c:87 [inline] ext4_sync_file+0x24f/0x680 fs/ext4/fsync.c:170 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2882 [inline] ext4_buffered_write_iter+0x34e/0x390 fs/ext4/file.c:277 ext4_file_write_iter+0x4a3/0xfd0 fs/ext4/file.c:498 call_write_iter include/linux/fs.h:1907 [inline] do_iter_readv_writev+0x321/0x3c0 fs/read_write.c:694 do_iter_write+0x10e/0x470 fs/read_write.c:999 vfs_iter_write+0x4c/0x70 fs/read_write.c:1040 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+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+0x71/0x120 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 18363 Comm: syz-executor.5 Not tainted 5.8.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================