================================================================== BUG: KCSAN: data-race in ext4_file_write_iter / ext4_writepages write to 0xffff8881234c8268 of 8 bytes by task 18552 on cpu 1: mpage_map_and_submit_extent fs/ext4/inode.c:2513 [inline] ext4_writepages+0x141a/0x1d70 fs/ext4/inode.c:2806 do_writepages+0x26b/0x3c0 mm/page-writeback.c:2364 filemap_fdatawrite_wbc mm/filemap.c:400 [inline] __filemap_fdatawrite_range mm/filemap.c:433 [inline] file_write_and_wait_range+0x1ae/0x240 mm/filemap.c:810 ext4_sync_file+0x105/0x670 fs/ext4/fsync.c:151 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2955 [inline] ext4_buffered_write_iter+0x3af/0x400 fs/ext4/file.c:277 ext4_file_write_iter+0x2f4/0x11f0 call_write_iter include/linux/fs.h:2163 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x79c/0x8d0 fs/read_write.c:594 ksys_write+0xd9/0x190 fs/read_write.c:647 __do_sys_write fs/read_write.c:659 [inline] __se_sys_write fs/read_write.c:656 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:656 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff8881234c8268 of 8 bytes by task 18542 on cpu 0: ext4_handle_inode_extension fs/ext4/file.c:300 [inline] ext4_dio_write_iter fs/ext4/file.c:574 [inline] ext4_file_write_iter+0xb32/0x11f0 fs/ext4/file.c:678 call_write_iter include/linux/fs.h:2163 [inline] do_iter_readv_writev+0x2de/0x380 fs/read_write.c:729 do_iter_write+0x192/0x5c0 fs/read_write.c:855 vfs_iter_write+0x4c/0x70 fs/read_write.c:896 iter_file_splice_write+0x43a/0x790 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:936 splice_direct_to_actor+0x345/0x650 fs/splice.c:891 do_splice_direct+0x106/0x190 fs/splice.c:979 do_sendfile+0x63e/0xbb0 fs/read_write.c:1249 __do_sys_sendfile64 fs/read_write.c:1314 [inline] __se_sys_sendfile64 fs/read_write.c:1300 [inline] __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1300 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000000000040000 -> 0x0000000000800000 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 18542 Comm: syz-executor.2 Tainted: G W 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================