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BUG: KASAN: use-after-free in sysv_new_inode+0xed4/0x1190 fs/sysv/ialloc.c:153
Read of size 2 at addr ffff888051edc1ce by task syz-executor.2/6315

CPU: 3 PID: 6315 Comm: syz-executor.2 Not tainted 6.10.0-rc2-syzkaller-00361-g061d1af7b030 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 sysv_new_inode+0xed4/0x1190 fs/sysv/ialloc.c:153
 sysv_symlink+0x97/0x180 fs/sysv/namei.c:80
 vfs_symlink fs/namei.c:4489 [inline]
 vfs_symlink+0x3e8/0x660 fs/namei.c:4473
 do_symlinkat+0x263/0x310 fs/namei.c:4515
 __do_sys_symlink fs/namei.c:4536 [inline]
 __se_sys_symlink fs/namei.c:4534 [inline]
 __x64_sys_symlink+0x79/0xa0 fs/namei.c:4534
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fead667cee9
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:00007fead74a00c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007fead67abf80 RCX: 00007fead667cee9
RDX: 0000000000000000 RSI: 0000000020000e40 RDI: 0000000020001640
RBP: 00007fead66c949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fead67abf80 R15: 00007ffcb9c5ae28
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x6d349 pfn:0x51edc
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffff7f(buddy)
raw: 00fff00000000000 ffffea00014b8508 ffffea000143a808 0000000000000000
raw: 000000000006d349 0000000000000002 00000000ffffff7f 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 6315, tgid 6314 (syz-executor.2), ts 239256856632, free_ts 258218850837
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1468
 prep_new_page mm/page_alloc.c:1476 [inline]
 get_page_from_freelist+0x136a/0x2e50 mm/page_alloc.c:3420
 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4678
 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2265
 folio_alloc_noprof+0x1e/0xc0 mm/mempolicy.c:2343
 filemap_alloc_folio_noprof+0x3ba/0x490 mm/filemap.c:1008
 do_read_cache_folio+0x1b6/0x540 mm/filemap.c:3752
 do_read_cache_page mm/filemap.c:3854 [inline]
 read_cache_page+0x5b/0x160 mm/filemap.c:3863
 read_mapping_page include/linux/pagemap.h:896 [inline]
 dir_get_page fs/sysv/dir.c:64 [inline]
 sysv_find_entry+0x1e5/0x690 fs/sysv/dir.c:157
 sysv_inode_by_name+0x71/0x3b0 fs/sysv/dir.c:374
 sysv_lookup fs/sysv/namei.c:38 [inline]
 sysv_lookup+0x8c/0x100 fs/sysv/namei.c:31
 lookup_one_qstr_excl+0x11d/0x190 fs/namei.c:1607
 filename_create+0x1ed/0x530 fs/namei.c:3901
 do_symlinkat+0xbf/0x310 fs/namei.c:4508
 __do_sys_symlink fs/namei.c:4536 [inline]
 __se_sys_symlink fs/namei.c:4534 [inline]
 __x64_sys_symlink+0x79/0xa0 fs/namei.c:4534
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
page last free pid 6315 tgid 6314 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1088 [inline]
 free_unref_folios+0x991/0x1310 mm/page_alloc.c:2632
 shrink_folio_list+0x348a/0x4150 mm/vmscan.c:1446
 evict_folios+0x6e6/0x1bf0 mm/vmscan.c:4553
 try_to_shrink_lruvec+0x618/0x9b0 mm/vmscan.c:4749
 lru_gen_shrink_lruvec mm/vmscan.c:4892 [inline]
 shrink_lruvec+0x2df/0x2a00 mm/vmscan.c:5669
 shrink_node_memcgs mm/vmscan.c:5889 [inline]
 shrink_node+0x818/0x39b0 mm/vmscan.c:5924
 shrink_zones mm/vmscan.c:6168 [inline]
 do_try_to_free_pages+0x35f/0x1940 mm/vmscan.c:6230
 try_to_free_mem_cgroup_pages+0x317/0x7f0 mm/vmscan.c:6545
 try_charge_memcg+0x35d/0x10b0 mm/memcontrol.c:2944
 obj_cgroup_charge_pages mm/memcontrol.c:3416 [inline]
 obj_cgroup_charge+0x179/0x4c0 mm/memcontrol.c:3705
 __memcg_slab_post_alloc_hook+0x18a/0x890 mm/memcontrol.c:3766
 memcg_slab_post_alloc_hook mm/slub.c:2104 [inline]
 slab_post_alloc_hook mm/slub.c:3962 [inline]
 slab_alloc_node mm/slub.c:4001 [inline]
 kmem_cache_alloc_noprof+0x2c6/0x2f0 mm/slub.c:4008
 alloc_buffer_head+0x21/0x160 fs/buffer.c:3028
 folio_alloc_buffers+0x2c1/0x780 fs/buffer.c:931
 create_empty_buffers+0x36/0x480 fs/buffer.c:1673
 folio_create_buffers+0x109/0x150 fs/buffer.c:1784

Memory state around the buggy address:
 ffff888051edc080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888051edc100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888051edc180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff888051edc200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888051edc280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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