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BUG: KASAN: use-after-free in reiserfs_release_objectid+0x525/0x780 fs/reiserfs/objectid.c:165
Read of size 8188 at addr ffff888053d57050 by task syz-executor/4269

CPU: 0 PID: 4269 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x235/0x290 mm/kasan/generic.c:189
 memmove+0x25/0x60 mm/kasan/shadow.c:54
 reiserfs_release_objectid+0x525/0x780 fs/reiserfs/objectid.c:165
 remove_save_link+0x2af/0x3e0 fs/reiserfs/super.c:542
 reiserfs_evict_inode+0x3ae/0x4c0 fs/reiserfs/inode.c:91
 evict+0x4c9/0x8d0 fs/inode.c:705
 do_unlinkat+0x388/0x580 fs/namei.c:4405
 __do_sys_unlink fs/namei.c:4446 [inline]
 __se_sys_unlink fs/namei.c:4444 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4444
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3b1919b907
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd2ae8b388 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3b1919b907
RDX: 00007ffd2ae8b3b0 RSI: 00007ffd2ae8b440 RDI: 00007ffd2ae8b440
RBP: 00007ffd2ae8b440 R08: 00007ffd2ae8c440 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd2ae8c530
R13: 00007f3b19232048 R14: 0000000000023499 R15: 00007ffd2ae8d600
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00014f55c0 refcount:2 mapcount:0 mapping:ffff8880178749f8 index:0x10 pfn:0x53d57
memcg:ffff88807a440000
aops:def_blk_aops ino:700001
flags: 0xfff58000022056(referenced|uptodate|lru|workingset|private|mappedtodisk|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff58000022056 ffffea00014e1fc8 ffffea000134a7c8 ffff8880178749f8
raw: 0000000000000010 ffff8880713d00e8 00000002ffffffff ffff88807a440000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x148c48(GFP_NOFS|__GFP_NOFAIL|__GFP_COMP|__GFP_HARDWALL|__GFP_MOVABLE), pid 4991, tgid 4990 (syz.1.111), ts 141520703771, free_ts 140812380853
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
 prep_new_page mm/page_alloc.c:2566 [inline]
 get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657
 folio_alloc+0x1c/0x60 mm/mempolicy.c:2292
 filemap_alloc_folio+0xdb/0x480 mm/filemap.c:999
 __filemap_get_folio+0x6ab/0xdb0 mm/filemap.c:1993
 pagecache_get_page+0x26/0x250 mm/folio-compat.c:110
 find_or_create_page include/linux/pagemap.h:648 [inline]
 grow_dev_page fs/buffer.c:946 [inline]
 grow_buffers fs/buffer.c:1011 [inline]
 __getblk_slow fs/buffer.c:1038 [inline]
 __getblk_gfp+0x2d8/0xb20 fs/buffer.c:1333
 __bread_gfp+0x26/0x330 fs/buffer.c:1367
 sb_bread include/linux/buffer_head.h:338 [inline]
 read_super_block+0x91/0x7c0 fs/reiserfs/super.c:1604
 reiserfs_fill_super+0x7a9/0x23b0 fs/reiserfs/super.c:1966
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1486 [inline]
 free_pcp_prepare mm/page_alloc.c:1536 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3554
 release_pages+0x1fa6/0x2220 mm/swap.c:1035
 __pagevec_release+0x6d/0xe0 mm/swap.c:1055
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x7c2/0x20c0 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x25b/0xa80 mm/shmem.c:1171
 evict+0x4c9/0x8d0 fs/inode.c:705
 __dentry_kill+0x431/0x650 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfa/0x1d0 fs/dcache.c:918
 __fput+0x5e0/0x920 fs/file_table.c:328
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x982/0x2480 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871

Memory state around the buggy address:
 ffff888053d57f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888053d57f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888053d58000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888053d58080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888053d58100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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