================================================================== BUG: KCSAN: data-race in copy_page_to_iter / fat16_ent_put write to 0xffff88813fc8720c of 2 bytes by task 18471 on cpu 1: fat16_ent_put+0x24/0x50 fs/fat/fatent.c:181 fat_alloc_clusters+0x430/0xa50 fs/fat/fatent.c:501 fat_add_cluster fs/fat/inode.c:108 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x213/0x5a0 fs/fat/inode.c:190 __block_write_begin_int+0x4a2/0x1060 fs/buffer.c:2006 __block_write_begin fs/buffer.c:2056 [inline] block_write_begin fs/buffer.c:2116 [inline] cont_write_begin+0x522/0x850 fs/buffer.c:2465 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 generic_perform_write+0x196/0x3c0 mm/filemap.c:3656 __generic_file_write_iter+0x161/0x300 mm/filemap.c:3783 generic_file_write_iter+0x75/0x130 mm/filemap.c:3815 call_write_iter include/linux/fs.h:2114 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x69d/0x770 fs/read_write.c:605 ksys_write+0xce/0x180 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:667 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88813fc87000 of 4096 bytes by task 18449 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:801 [inline] copy_page_to_iter+0x2e1/0x940 lib/iov_iter.c:829 filemap_read+0xef6/0x1220 mm/filemap.c:2605 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701 blkdev_read_iter+0xb9/0xf0 fs/block_dev.c:1669 call_read_iter include/linux/fs.h:2108 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x565/0x5d0 fs/read_write.c:496 ksys_read+0xce/0x180 fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] __se_sys_read fs/read_write.c:642 [inline] __x64_sys_read+0x3e/0x50 fs/read_write.c:642 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 18449 Comm: systemd-udevd Tainted: G W 5.14.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================