================================================================== BUG: KCSAN: data-race in _copy_to_iter / fat16_ent_put write to 0xffff888138bb9218 of 2 bytes by task 11427 on cpu 1: fat16_ent_put+0x24/0x50 fs/fat/fatent.c:183 fat_ent_write+0x5e/0xd0 fs/fat/fatent.c:417 fat_chain_add+0x15b/0x410 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+0x486/0x600 fs/fat/inode.c:190 __block_write_begin_int+0x2fd/0xb90 fs/buffer.c:2006 __block_write_begin fs/buffer.c:2056 [inline] block_write_begin+0x73/0x170 fs/buffer.c:2117 cont_write_begin+0x3f1/0x520 fs/buffer.c:2471 fat_write_begin+0x5d/0xe0 fs/fat/inode.c:235 generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738 __generic_file_write_iter+0xe3/0x280 mm/filemap.c:3866 generic_file_write_iter+0x79/0x1c0 mm/filemap.c:3898 call_write_iter include/linux/fs.h:2187 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x468/0x760 fs/read_write.c:578 ksys_write+0xe8/0x1a0 fs/read_write.c:631 __do_sys_write fs/read_write.c:643 [inline] __se_sys_write fs/read_write.c:640 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:640 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff888138bb9000 of 1377 bytes by task 25248 on cpu 0: instrument_copy_to_user include/linux/instrumented.h:119 [inline] copyout lib/iov_iter.c:169 [inline] _copy_to_iter+0x11d/0x8b0 lib/iov_iter.c:524 copy_page_to_iter+0x333/0x3f0 lib/iov_iter.c:722 copy_folio_to_iter include/linux/uio.h:169 [inline] filemap_read+0x119b/0x1430 mm/filemap.c:2711 blkdev_read_iter+0x2c6/0x370 block/fops.c:598 call_read_iter include/linux/fs.h:2181 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x3a5/0x560 fs/read_write.c:470 ksys_read+0xe8/0x1a0 fs/read_write.c:607 __do_sys_read fs/read_write.c:617 [inline] __se_sys_read fs/read_write.c:615 [inline] __x64_sys_read+0x3e/0x50 fs/read_write.c:615 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 25248 Comm: udevd Not tainted 6.0.0-rc3-syzkaller-00215-g0b3acd1cc022-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 ================================================================== I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop4, logical block 0, async page read I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop1, logical block 0, async page read I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop4, logical block 0, async page read I/O error, dev loop5, sector 8 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2 I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop4, logical block 0, async page read I/O error, dev loop5, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop5, logical block 0, async page read I/O error, dev loop5, sector 4 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop5, logical block 2, async page read I/O error, dev loop5, sector 6 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop5, logical block 3, async page read I/O error, dev loop5, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev loop5, logical block 0, async page read