VFS: Found a Xenix FS (block size = 1024) on device loop2
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BUG: KASAN: use-after-free in sysv_new_inode+0x10b4/0x1240 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff8880571071ce by task syz.2.58/4682

CPU: 0 PID: 4682 Comm: syz.2.58 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 sysv_new_inode+0x10b4/0x1240 fs/sysv/ialloc.c:153
 sysv_mknod+0x4a/0xd0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3462 [inline]
 open_last_lookups fs/namei.c:3532 [inline]
 path_openat+0x11e1/0x2f30 fs/namei.c:3739
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769
 do_sys_openat2+0x142/0x4a0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1280
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6c91c2abe9
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:00007f6c8fe92038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6c91e51fa0 RCX: 00007f6c91c2abe9
RDX: 0000000000000042 RSI: 0000200000000440 RDI: ffffffffffffff9c
RBP: 00007f6c91cade19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6c91e52038 R14: 00007f6c91e51fa0 R15: 00007fff5c0ecc68
 </TASK>

The buggy address belongs to the page:
page:ffffea00015c41c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x100 pfn:0x57107
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00015c4208 ffffea00015c4188 0000000000000000
raw: 0000000000000100 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 0x8(__GFP_MOVABLE), pid 1, ts 11140355341, free_ts 11889886185
 split_map_pages+0x277/0x4c0 mm/compaction.c:99
 isolate_freepages_range+0x3dd/0x430 mm/compaction.c:749
 alloc_contig_range+0x97e/0xcd0 mm/page_alloc.c:9267
 __alloc_contig_pages mm/page_alloc.c:9291 [inline]
 alloc_contig_pages+0x390/0x490 mm/page_alloc.c:9371
 debug_vm_pgtable_alloc_huge_page+0xbf/0x110 mm/debug_vm_pgtable.c:1085
 init_args+0xb3a/0xdd0 mm/debug_vm_pgtable.c:1207
 debug_vm_pgtable+0x42/0x370 mm/debug_vm_pgtable.c:1245
 do_one_initcall+0x1ee/0x680 init/main.c:1302
 do_initcall_level+0x137/0x1f0 init/main.c:1375
 do_initcalls+0x4b/0x90 init/main.c:1391
 kernel_init_freeable+0x3ce/0x560 init/main.c:1615
 kernel_init+0x19/0x1b0 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x94/0x280 mm/page_alloc.c:3396
 free_contig_range+0x96/0xf0 mm/page_alloc.c:9393
 destroy_args+0xef/0x8b0 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x318/0x370 mm/debug_vm_pgtable.c:1331
 do_one_initcall+0x1ee/0x680 init/main.c:1302
 do_initcall_level+0x137/0x1f0 init/main.c:1375
 do_initcalls+0x4b/0x90 init/main.c:1391
 kernel_init_freeable+0x3ce/0x560 init/main.c:1615
 kernel_init+0x19/0x1b0 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff888057107080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888057107100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888057107180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff888057107200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888057107280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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