loop8: detected capacity change from 0 to 256
exFAT-fs (loop8): failed to load upcase table (idx : 0x00010000, chksum : 0x1a9973fb, utbl_chksum : 0xe619d30d)
=====================================================
BUG: KMSAN: uninit-value in iov_iter_alignment_iovec+0x1a8/0x470 lib/iov_iter.c:894
 iov_iter_alignment_iovec+0x1a8/0x470 lib/iov_iter.c:894
 iov_iter_alignment+0x1ac/0x2d0 lib/iov_iter.c:939
 exfat_file_write_iter+0x1df/0xcb0 fs/exfat/file.c:594
 io_write+0xd41/0x2380 io_uring/rw.c:1110
 io_issue_sqe+0x436/0x1fb0 io_uring/io_uring.c:1737
 io_queue_sqe io_uring/io_uring.c:1947 [inline]
 io_submit_sqe io_uring/io_uring.c:2204 [inline]
 io_submit_sqes+0x11c3/0x2ff0 io_uring/io_uring.c:2321
 __do_sys_io_uring_enter io_uring/io_uring.c:3372 [inline]
 __se_sys_io_uring_enter+0x41d/0x4da0 io_uring/io_uring.c:3307
 __ia32_sys_io_uring_enter+0x11d/0x1a0 io_uring/io_uring.c:3307
 ia32_sys_call+0xd59/0x4180 arch/x86/include/generated/asm/syscalls_32.h:427
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4121 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 __do_kmalloc_node mm/slub.c:4293 [inline]
 __kmalloc_noprof+0x923/0x1230 mm/slub.c:4306
 kmalloc_noprof include/linux/slab.h:905 [inline]
 io_cache_alloc_new+0x54/0x140 io_uring/alloc_cache.c:40
 io_cache_alloc io_uring/alloc_cache.h:68 [inline]
 io_uring_alloc_async_data io_uring/io_uring.h:232 [inline]
 io_rw_alloc_async io_uring/rw.c:206 [inline]
 io_prep_rw_setup io_uring/rw.c:219 [inline]
 io_prep_rw+0x90e/0x1380 io_uring/rw.c:303
 io_prep_rwv+0xb3/0x510 io_uring/rw.c:338
 io_prep_writev+0x3a/0x50 io_uring/rw.c:358
 io_init_req io_uring/io_uring.c:2119 [inline]
 io_submit_sqe io_uring/io_uring.c:2166 [inline]
 io_submit_sqes+0x1089/0x2ff0 io_uring/io_uring.c:2321
 __do_sys_io_uring_enter io_uring/io_uring.c:3372 [inline]
 __se_sys_io_uring_enter+0x41d/0x4da0 io_uring/io_uring.c:3307
 __ia32_sys_io_uring_enter+0x11d/0x1a0 io_uring/io_uring.c:3307
 ia32_sys_call+0xd59/0x4180 arch/x86/include/generated/asm/syscalls_32.h:427
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

CPU: 0 UID: 0 PID: 7372 Comm: syz.8.333 Not tainted 6.14.0-rc5-syzkaller-00016-g48a5eed9ad58 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
=====================================================