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BUG: KASAN: use-after-free in ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500
Read of size 1 at addr ffff88805934bcaa by task syz.0.181/7271

CPU: 0 UID: 0 PID: 7271 Comm: syz.0.181 Not tainted 6.11.0-rc6-syzkaller-00017-gc9f016e72b5c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 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
 ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500
 ext4_find_inline_entry+0x4be/0x5e0 fs/ext4/inline.c:1697
 __ext4_find_entry+0x2b4/0x1b30 fs/ext4/namei.c:1573
 ext4_lookup_entry fs/ext4/namei.c:1727 [inline]
 ext4_lookup+0x15f/0x750 fs/ext4/namei.c:1795
 lookup_one_qstr_excl+0x11f/0x260 fs/namei.c:1633
 do_rmdir+0x297/0x580 fs/namei.c:4341
 __do_sys_rmdir fs/namei.c:4371 [inline]
 __se_sys_rmdir fs/namei.c:4369 [inline]
 __x64_sys_rmdir+0x47/0x50 fs/namei.c:4369
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb301979eb9
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:00007fb302802038 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00007fb301b16058 RCX: 00007fb301979eb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200002c0
RBP: 00007fb3019e793e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fb301b16058 R15: 00007ffc15291d08
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7d pfn:0x5934b
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea000164d308 ffffea00016b5288 0000000000000000
raw: 000000000000007d 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 7269, tgid 7242 (syz.4.163), ts 248431703763, free_ts 248465542271
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2263
 folio_alloc_mpol_noprof+0x36/0x50 mm/mempolicy.c:2281
 shmem_alloc_folio mm/shmem.c:1722 [inline]
 shmem_alloc_and_add_folio+0x2cf/0x14f0 mm/shmem.c:1782
 shmem_get_folio_gfp+0x8dc/0x2370 mm/shmem.c:2188
 shmem_get_folio mm/shmem.c:2293 [inline]
 shmem_write_begin+0x170/0x4d0 mm/shmem.c:2898
 generic_perform_write+0x399/0x840 mm/filemap.c:4019
 shmem_file_write_iter+0xfc/0x120 mm/shmem.c:3074
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 7269 tgid 7242 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_folios+0x100f/0x1ac0 mm/page_alloc.c:2660
 folios_put_refs+0x76e/0x860 mm/swap.c:1039
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x6de/0x1df0 mm/shmem.c:1023
 shmem_truncate_range mm/shmem.c:1132 [inline]
 shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1260
 evict+0x532/0x950 fs/inode.c:704
 __dentry_kill+0x20d/0x630 fs/dcache.c:615
 dput+0x19f/0x2b0 fs/dcache.c:857
 __fput+0x5f8/0x8a0 fs/file_table.c:430
 __do_sys_close fs/open.c:1566 [inline]
 __se_sys_close fs/open.c:1551 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1551
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88805934bb80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805934bc00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805934bc80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                  ^
 ffff88805934bd00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805934bd80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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