==================================================================
BUG: KASAN: use-after-free in sysv_new_inode+0xfd3/0x1170 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff888044a2c1ce by task syz-executor.4/15173

CPU: 1 PID: 15173 Comm: syz-executor.4 Not tainted 6.9.0-rc5-syzkaller-00329-g5d12ed4bea43 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 sysv_new_inode+0xfd3/0x1170 fs/sysv/ialloc.c:153
 sysv_mknod+0x4e/0xe0 fs/sysv/namei.c:53
 lookup_open fs/namei.c:3497 [inline]
 open_last_lookups fs/namei.c:3566 [inline]
 path_openat+0x1425/0x3240 fs/namei.c:3796
 do_filp_open+0x235/0x490 fs/namei.c:3826
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_openat fs/open.c:1437 [inline]
 __se_sys_openat fs/open.c:1432 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1432
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f012187dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f01226450c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f01219ac120 RCX: 00007f012187dea9
RDX: 000000000000275a RSI: 00000000200001c0 RDI: ffffffffffffff9c
RBP: 00007f01218ca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f01219ac120 R15: 00007ffc3636df28
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x44a2c
flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000000 ffffea000121c1c8 ffffea0001bbb908 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 0x100cca(GFP_HIGHUSER_MOVABLE), pid 28368, tgid 1633309348 (syz-executor.4), ts 28369, free_ts 2046457944337
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
 alloc_pages_mpol+0x3e8/0x680 mm/mempolicy.c:2264
 shmem_alloc_folio mm/shmem.c:1628 [inline]
 shmem_alloc_and_add_folio+0x24d/0xbc0 mm/shmem.c:1668
 shmem_get_folio_gfp+0x82d/0x1f50 mm/shmem.c:2055
 shmem_fault+0x254/0x6f0 mm/shmem.c:2255
 __do_fault+0x135/0x460 mm/memory.c:4531
 do_read_fault mm/memory.c:4894 [inline]
 do_fault mm/memory.c:5024 [inline]
 do_pte_missing mm/memory.c:3880 [inline]
 handle_pte_fault mm/memory.c:5300 [inline]
 __handle_mm_fault+0x45fe/0x7250 mm/memory.c:5441
 handle_mm_fault+0x27f/0x770 mm/memory.c:5606
 faultin_page mm/gup.c:958 [inline]
 __get_user_pages+0x727/0x1630 mm/gup.c:1257
 populate_vma_page_range+0x2ae/0x390 mm/gup.c:1697
 __mm_populate+0x27a/0x460 mm/gup.c:1800
 mm_populate include/linux/mm.h:3413 [inline]
 vm_mmap_pgoff+0x305/0x420 mm/util.c:578
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 28370 tgid 28368 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x97b/0xaa0 mm/page_alloc.c:2347
 free_unref_folios+0x1f2/0xc10 mm/page_alloc.c:2536
 folios_put_refs+0x93a/0xa60 mm/swap.c:1034
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x6d9/0x1df0 mm/shmem.c:1005
 shmem_truncate_range mm/shmem.c:1114 [inline]
 shmem_evict_inode+0x29b/0xa60 mm/shmem.c:1242
 evict+0x2a8/0x630 fs/inode.c:667
 __dentry_kill+0x20d/0x630 fs/dcache.c:603
 dput+0x19f/0x2b0 fs/dcache.c:845
 __fput+0x678/0x8a0 fs/file_table.c:430
 task_work_run+0x24f/0x310 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xa1b/0x27e0 kernel/exit.c:878
 do_group_exit+0x207/0x2c0 kernel/exit.c:1027
 get_signal+0x16a1/0x1740 kernel/signal.c:2911
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218
 do_syscall_64+0x102/0x240 arch/x86/entry/common.c:89

Memory state around the buggy address:
 ffff888044a2c080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888044a2c100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888044a2c180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff888044a2c200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888044a2c280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================