================================================================== BUG: KCSAN: data-race in copy_page_to_iter / fat16_ent_put write to 0xffff88813ebfe248 of 2 bytes by task 10760 on cpu 1: fat16_ent_put+0x24/0x50 fs/fat/fatent.c:182 fat_alloc_clusters+0x493/0xab0 fs/fat/fatent.c:502 fat_add_cluster fs/fat/inode.c:108 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x267/0x610 fs/fat/inode.c:190 __block_write_begin_int+0x4c5/0x1010 fs/buffer.c:2010 __block_write_begin fs/buffer.c:2060 [inline] block_write_begin fs/buffer.c:2120 [inline] cont_write_begin+0x4cf/0x7b0 fs/buffer.c:2469 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 generic_perform_write+0x1c8/0x400 mm/filemap.c:3756 __generic_file_write_iter+0xf7/0x2b0 mm/filemap.c:3883 generic_file_write_iter+0x75/0x130 mm/filemap.c:3915 call_write_iter include/linux/fs.h:2162 [inline] new_sync_write fs/read_write.c:503 [inline] vfs_write+0x7f5/0x950 fs/read_write.c:590 ksys_write+0xd9/0x190 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:652 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88813ebfe000 of 4096 bytes by task 1902 on cpu 0: instrument_copy_to_user include/linux/instrumented.h:119 [inline] copyout lib/iov_iter.c:156 [inline] copy_page_to_iter_iovec lib/iov_iter.c:228 [inline] __copy_page_to_iter lib/iov_iter.c:852 [inline] copy_page_to_iter+0x2cb/0x950 lib/iov_iter.c:880 filemap_read+0x138b/0x16d0 mm/filemap.c:2697 generic_file_read_iter+0x72/0x2a0 mm/filemap.c:2792 blkdev_read_iter+0x96/0x140 block/fops.c:583 call_read_iter include/linux/fs.h:2156 [inline] new_sync_read fs/read_write.c:400 [inline] vfs_read+0x66c/0x750 fs/read_write.c:481 ksys_read+0xd9/0x190 fs/read_write.c:619 __do_sys_read fs/read_write.c:629 [inline] __se_sys_read fs/read_write.c:627 [inline] __x64_sys_read+0x3e/0x50 fs/read_write.c:627 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1902 Comm: udevd Not tainted 5.16.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================