================================================================== BUG: KCSAN: data-race in _copy_to_iter / fat16_ent_put write to 0xffff88813bfcc26e of 2 bytes by task 12629 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+0x3c3/0xf50 fs/buffer.c:2120 __block_write_begin fs/buffer.c:2169 [inline] block_write_begin+0x7b/0x170 fs/buffer.c:2228 cont_write_begin+0x479/0x690 fs/buffer.c:2585 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230 cont_expand_zero fs/buffer.c:2512 [inline] cont_write_begin+0x182/0x690 fs/buffer.c:2575 fat_write_begin+0x61/0xf0 fs/fat/inode.c:230 generic_cont_expand_simple+0xa7/0x140 fs/buffer.c:2476 fat_cont_expand+0x3a/0x160 fs/fat/file.c:223 fat_setattr+0x2a9/0x840 fs/fat/file.c:513 notify_change+0x866/0x8e0 fs/attr.c:499 do_truncate+0x116/0x150 fs/open.c:66 do_sys_ftruncate+0x2ba/0x3b0 fs/open.c:194 __do_sys_ftruncate fs/open.c:205 [inline] __se_sys_ftruncate fs/open.c:203 [inline] __x64_sys_ftruncate+0x33/0x40 fs/open.c:203 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 0xffff88813bfcc000 of 1377 bytes by task 3472 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:1950 [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: 3472 Comm: udevd Not tainted 6.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 ==================================================================