==================================================================
BUG: KASAN: use-after-free in sysv_new_inode+0x1130/0x12c0 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff88805cee61ce by task syz.3.13/4353

CPU: 1 PID: 4353 Comm: syz.3.13 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 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+0x1130/0x12c0 fs/sysv/ialloc.c:153
 sysv_mknod+0x4a/0xd0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3470 [inline]
 open_last_lookups fs/namei.c:3540 [inline]
 path_openat+0x11db/0x2fa0 fs/namei.c:3747
 do_filp_open+0x1e2/0x410 fs/namei.c:3777
 do_sys_openat2+0x150/0x4b0 fs/open.c:1255
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_openat fs/open.c:1287 [inline]
 __se_sys_openat fs/open.c:1282 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1282
 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: 0033:0x7ff2aff27f79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff2ae161028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff2b01a2090 RCX: 00007ff2aff27f79
RDX: 000000000000275a RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007ff2affbe7e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff2b01a2128 R14: 00007ff2b01a2090 R15: 00007fff5cff8c08
 </TASK>

The buggy address belongs to the page:
page:ffffea000173b980 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x5cee6
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea000173b9c8 ffffea000173b948 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 0x8(__GFP_MOVABLE), pid 1, ts 21099710225, free_ts 22107197961
 split_map_pages+0x280/0x4d0 mm/compaction.c:99
 isolate_freepages_range+0x3e5/0x440 mm/compaction.c:749
 alloc_contig_range+0x83b/0xd70 mm/page_alloc.c:9288
 __alloc_contig_pages mm/page_alloc.c:9312 [inline]
 alloc_contig_pages+0x390/0x490 mm/page_alloc.c:9392
 debug_vm_pgtable_alloc_huge_page+0xbf/0x110 mm/debug_vm_pgtable.c:1090
 init_args+0xb3a/0xdd0 mm/debug_vm_pgtable.c:1212
 debug_vm_pgtable+0x42/0x380 mm/debug_vm_pgtable.c:1250
 do_one_initcall+0x272/0x730 init/main.c:1316
 do_initcall_level+0x137/0x1f0 init/main.c:1389
 do_initcalls+0x4b/0x90 init/main.c:1405
 kernel_init_freeable+0x3e9/0x570 init/main.c:1629
 kernel_init+0x19/0x1b0 init/main.c:1520
 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+0x8f/0x2a0 mm/page_alloc.c:3396
 free_contig_range+0x96/0xf0 mm/page_alloc.c:9414
 destroy_args+0xf0/0xa00 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x321/0x380 mm/debug_vm_pgtable.c:1336
 do_one_initcall+0x272/0x730 init/main.c:1316
 do_initcall_level+0x137/0x1f0 init/main.c:1389
 do_initcalls+0x4b/0x90 init/main.c:1405
 kernel_init_freeable+0x3e9/0x570 init/main.c:1629
 kernel_init+0x19/0x1b0 init/main.c:1520
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff88805cee6080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805cee6100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805cee6180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88805cee6200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805cee6280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================