================================================================== BUG: KCSAN: data-race in copy_page_to_iter / fat12_ent_put write to 0xffff888130d06206 of 1 bytes by task 30881 on cpu 1: fat12_ent_put+0x76/0x1b0 fs/fat/fatent.c:166 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:2031 __block_write_begin fs/buffer.c:2081 [inline] block_write_begin fs/buffer.c:2141 [inline] cont_write_begin+0x522/0x850 fs/buffer.c:2490 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 generic_perform_write+0x196/0x3a0 mm/filemap.c:3660 __generic_file_write_iter+0x202/0x300 mm/filemap.c:3757 generic_file_write_iter+0x75/0x130 mm/filemap.c:3821 call_write_iter include/linux/fs.h:2114 [inline] do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740 do_iter_write+0x112/0x4c0 fs/read_write.c:866 vfs_iter_write+0x4c/0x70 fs/read_write.c:907 iter_file_splice_write+0x40a/0x750 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:936 splice_direct_to_actor+0x345/0x650 fs/splice.c:891 do_splice_direct+0xf5/0x170 fs/splice.c:979 do_sendfile+0x773/0xda0 fs/read_write.c:1260 __do_sys_sendfile64 fs/read_write.c:1325 [inline] __se_sys_sendfile64 fs/read_write.c:1311 [inline] __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888130d06000 of 1024 bytes by task 30859 on cpu 0: instrument_copy_to_user include/linux/instrumented.h:119 [inline] copyout lib/iov_iter.c:189 [inline] copy_page_to_iter_iovec lib/iov_iter.c:261 [inline] copy_page_to_iter+0x320/0x860 lib/iov_iter.c:973 filemap_read+0xf06/0x1230 mm/filemap.c:2605 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701 blkdev_read_iter+0xb9/0xf0 fs/block_dev.c:1730 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_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 30859 Comm: systemd-udevd Not tainted 5.13.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================