loop2: detected capacity change from 0 to 128
VFS: Found a Xenix FS (block size = 1024) on device loop2
syz.2.19: attempt to access beyond end of device
loop2: rw=0, sector=6491536, nr_sectors = 2 limit=128
Buffer I/O error on dev loop2, logical block 3245768, async page read
==================================================================
BUG: KASAN: use-after-free in sysv_new_inode+0xf09/0x10c0 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff88806e56b1ce by task syz.2.19/4603

CPU: 1 PID: 4603 Comm: syz.2.19 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe0/0x160 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 sysv_new_inode+0xf09/0x10c0 fs/sysv/ialloc.c:153
 sysv_mknod+0x29/0xa0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3488 [inline]
 open_last_lookups fs/namei.c:3556 [inline]
 path_openat+0xee0/0x2790 fs/namei.c:3786
 do_filp_open+0x1b4/0x370 fs/namei.c:3816
 do_sys_openat2+0xf9/0x180 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0xf4/0x120 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f067838e929
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:00007f067919c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f06785b5fa0 RCX: 00007f067838e929
RDX: 0000000000101042 RSI: 0000200000000180 RDI: ffffffffffffff9c
RBP: 00007f0678410b39 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001b6 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f06785b5fa0 R15: 00007ffd2c0e1538
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001b95ac0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6e56b
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 ffffea0001b25f48 ffffea0001b2c208 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO), pid 4603, tgid 4602 (syz.2.19), ts 75872330577, free_ts 75874536734
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x26b/0x290 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x2a35/0x2b70 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x430 mm/page_alloc.c:4457
 __folio_alloc+0x10/0x20 mm/page_alloc.c:4489
 vma_alloc_folio+0x47d/0x9d0 mm/mempolicy.c:2242
 do_anonymous_page mm/memory.c:4149 [inline]
 do_pte_missing+0xc22/0x2090 mm/memory.c:3686
 handle_pte_fault mm/memory.c:5025 [inline]
 __handle_mm_fault mm/memory.c:5166 [inline]
 handle_mm_fault+0xd97/0x1d90 mm/memory.c:5331
 do_user_addr_fault+0x786/0xb70 arch/x86/mm/fault.c:1324
 handle_page_fault arch/x86/mm/fault.c:1465 [inline]
 exc_page_fault+0x52/0xc0 arch/x86/mm/fault.c:1521
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7d5/0x8e0 mm/page_alloc.c:2336
 free_unref_page_list+0xbe/0x7c0 mm/page_alloc.c:2475
 release_pages+0x14d0/0x1650 mm/swap.c:1022
 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu+0x288/0x3f0 mm/mmu_gather.c:300
 tlb_finish_mmu+0xaa/0x190 mm/mmu_gather.c:392
 unmap_region+0x2d4/0x320 mm/mmap.c:2345
 do_vmi_align_munmap+0xb91/0x1160 mm/mmap.c:2588
 do_vmi_munmap+0x190/0x200 mm/mmap.c:2656
 __vm_munmap+0x16d/0x310 mm/mmap.c:2957
 __do_sys_munmap mm/mmap.c:2974 [inline]
 __se_sys_munmap mm/mmap.c:2971 [inline]
 __x64_sys_munmap+0x5b/0x70 mm/mmap.c:2971
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88806e56b080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806e56b100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806e56b180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88806e56b200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806e56b280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================