=========================================[  993.395992][T12817] ==================================================================
BUG: KASAN: stack-out-of-bounds in exfat_nls_to_ucs2 fs/exfat/nls.c:619 [inline]
BUG: KASAN: stack-out-of-bounds in exfat_nls_to_utf16+0xac8/0xc10 fs/exfat/nls.c:647
Read of size 1 at addr ffffc900062776f0 by task syz.5.644/12817

CPU: 0 UID: 0 PID: 12817 Comm: syz.5.644 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 exfat_nls_to_ucs2 fs/exfat/nls.c:619 [inline]
 exfat_nls_to_utf16+0xac8/0xc10 fs/exfat/nls.c:647
 exfat_ioctl_set_volume_label fs/exfat/file.c:524 [inline]
 exfat_ioctl+0x818/0x1100 fs/exfat/file.c:554
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa48c6deec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa48a91d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa48c936090 RCX: 00007fa48c6deec9
RDX: 0000200000000800 RSI: 0000000041009432 RDI: 0000000000000005
RBP: 00007fa48c761f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa48c936128 R14: 00007fa48c936090 R15: 00007ffc4638acf8
 </TASK>

The buggy address belongs to stack of task syz.5.644/12817
 and is located at offset 304 in frame:
 exfat_ioctl+0x0/0x1100 fs/exfat/file.c:33

This frame has 7 objects:
 [32, 36) 'lossy.i'
 [48, 304) 'label.i50'
 [368, 888) 'uniname.i51'
 [1024, 1280) 'label.i'
 [1344, 1864) 'uniname.i'
 [2000, 2024) 'range.i'
 [2064, 2144) 'ia.i'

The buggy address belongs to a 8-page vmalloc region starting at 0xffffc90006270000 allocated at copy_process+0x545/0x3ae0 kernel/fork.c:2012
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xfce pfn:0x3ef85
memcg:ffff88805c801482
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000fce 0000000000000000 00000001ffffffff ffff88805c801482
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO|__GFP_NOWARN), pid 12763, tgid 12763 (syz.1.635), ts 988138964427, free_ts 987668068565
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
 alloc_pages_noprof+0xcf/0x1e0 mm/mempolicy.c:2507
 vm_area_alloc_pages mm/vmalloc.c:3647 [inline]
 __vmalloc_area_node mm/vmalloc.c:3724 [inline]
 __vmalloc_node_range_noprof+0x96c/0x12d0 mm/vmalloc.c:3897
 __vmalloc_node_noprof+0xc2/0x110 mm/vmalloc.c:3960
 alloc_thread_stack_node kernel/fork.c:311 [inline]
 dup_task_struct+0x3d4/0x830 kernel/fork.c:881
 copy_process+0x545/0x3ae0 kernel/fork.c:2012
 kernel_clone+0x224/0x7c0 kernel/fork.c:2609
 __do_sys_clone3 kernel/fork.c:2911 [inline]
 __se_sys_clone3+0x256/0x2d0 kernel/fork.c:2890
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 11303 tgid 11303 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 free_unref_folios+0xc22/0x1860 mm/page_alloc.c:2963
 folios_put_refs+0x569/0x670 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 mapping_try_invalidate+0x324/0x410 mm/truncate.c:554
 btrfs_close_bdev fs/btrfs/volumes.c:1125 [inline]
 btrfs_close_one_device fs/btrfs/volumes.c:1149 [inline]
 close_fs_devices+0x448/0x870 fs/btrfs/volumes.c:1192
 btrfs_close_devices+0xc5/0x560 fs/btrfs/volumes.c:1207
 btrfs_free_fs_info+0x4f/0x3c0 fs/btrfs/disk-io.c:1249
 deactivate_locked_super+0xbc/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffffc90006277580: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04 f2 00 00
 ffffc90006277600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90006277680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2
                                                             ^
 ffffc90006277700: f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 00
 ffffc90006277780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================