================================================================== BUG: KCSAN: data-race in _copy_to_iter / fat16_ent_put write to 0xffff88813aff0258 of 2 bytes by task 10831 on cpu 1: fat16_ent_put+0x28/0x60 fs/fat/fatent.c:183 fat_ent_write+0x62/0xe0 fs/fat/fatent.c:417 fat_chain_add+0x15f/0x400 fs/fat/misc.c:136 fat_add_cluster fs/fat/inode.c:113 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x467/0x5e0 fs/fat/inode.c:190 __block_write_begin_int+0x3c0/0xf20 fs/buffer.c:2107 __block_write_begin fs/buffer.c:2157 [inline] block_write_begin+0x7b/0x170 fs/buffer.c:2216 cont_write_begin+0x479/0x690 fs/buffer.c:2573 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230 generic_perform_write+0x1c9/0x410 mm/filemap.c:3942 __generic_file_write_iter+0xa1/0x120 mm/filemap.c:4037 generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4063 call_write_iter include/linux/fs.h:1985 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x4ab/0x7d0 fs/read_write.c:584 ksys_write+0xeb/0x1a0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x42/0x50 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff88813aff0000 of 1377 bytes by task 3347 on cpu 0: instrument_copy_to_user include/linux/instrumented.h:113 [inline] copyout lib/iov_iter.c:167 [inline] _copy_to_iter+0x12b/0x950 lib/iov_iter.c:316 copy_page_to_iter+0x171/0x2b0 lib/iov_iter.c:481 copy_folio_to_iter include/linux/uio.h:185 [inline] filemap_read+0x424/0x680 mm/filemap.c:2703 blkdev_read_iter+0x217/0x2c0 block/fops.c:730 call_read_iter include/linux/fs.h:1979 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x3da/0x5c0 fs/read_write.c:470 ksys_read+0xeb/0x1a0 fs/read_write.c:613 __do_sys_read fs/read_write.c:623 [inline] __se_sys_read fs/read_write.c:621 [inline] __x64_sys_read+0x42/0x50 fs/read_write.c:621 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 3347 Comm: udevd Not tainted 6.6.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 ==================================================================