loop4: detected capacity change from 0 to 256
exFAT-fs (loop4): failed to load upcase table (idx : 0x00010000, chksum : 0xc14df490, utbl_chksum : 0xe619d30d)
=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:30 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x2f3/0x2b30 lib/iov_iter.c:185
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_ubuf include/linux/iov_iter.h:30 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 _copy_to_iter+0x2f3/0x2b30 lib/iov_iter.c:185
 copy_page_to_iter+0x419/0x880 lib/iov_iter.c:362
 copy_folio_to_iter include/linux/uio.h:189 [inline]
 filemap_read+0xc13/0x1500 mm/filemap.c:2696
 generic_file_read_iter+0x136/0xad0 mm/filemap.c:2833
 new_sync_read fs/read_write.c:488 [inline]
 vfs_read+0xcdf/0xf50 fs/read_write.c:569
 ksys_read+0x24f/0x4c0 fs/read_write.c:712
 __do_sys_read fs/read_write.c:722 [inline]
 __se_sys_read fs/read_write.c:720 [inline]
 __x64_sys_read+0x93/0xe0 fs/read_write.c:720
 x64_sys_call+0x3055/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4756
 alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
 alloc_pages_noprof mm/mempolicy.c:2345 [inline]
 folio_alloc_noprof+0x1db/0x310 mm/mempolicy.c:2352
 filemap_alloc_folio_noprof+0xa6/0x440 mm/filemap.c:1010
 __filemap_get_folio+0xac4/0x1550 mm/filemap.c:1952
 block_write_begin+0x6e/0x2b0 fs/buffer.c:2226
 exfat_write_begin+0xfb/0x400 fs/exfat/inode.c:434
 exfat_extend_valid_size fs/exfat/file.c:553 [inline]
 exfat_page_mkwrite+0x4ef/0xaf0 fs/exfat/file.c:639
 do_page_mkwrite mm/memory.c:3162 [inline]
 do_shared_fault mm/memory.c:5373 [inline]
 do_fault mm/memory.c:5435 [inline]
 do_pte_missing mm/memory.c:3965 [inline]
 handle_pte_fault mm/memory.c:5766 [inline]
 __handle_mm_fault mm/memory.c:5909 [inline]
 handle_mm_fault+0x8ad9/0xdc30 mm/memory.c:6077
 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x29f/0x700 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:623

Bytes 0-4095 of 4096 are uninitialized
Memory access of size 4096 starts at ffff88805761e000
Data copied to user address 0000000020001cc0

CPU: 1 UID: 0 PID: 23109 Comm: syz.4.4948 Not tainted 6.12.0-rc5-syzkaller-00181-g6c52d4da1c74 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================