REISERFS warning (device loop4): vs-13060 reiserfs_update_sd_size: stat data of object [2 5 0x0 SD] (nlink == 1) not found (pos 2)
REISERFS warning (device loop4): vs-13060 reiserfs_update_sd_size: stat data of object [3 6 0x0 SD] (nlink == 2) not found (pos 1)
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BUG: KASAN: use-after-free in bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
BUG: KASAN: use-after-free in search_by_entry_key+0x597/0x1370 fs/reiserfs/namei.c:165
Read of size 4 at addr ffff88804ba4cfc4 by task syz.4.324/5700

CPU: 1 PID: 5700 Comm: syz.4.324 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
 bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
 search_by_entry_key+0x597/0x1370 fs/reiserfs/namei.c:165
 reiserfs_find_entry+0x2f2/0x18e0 fs/reiserfs/namei.c:322
 reiserfs_lookup+0x1e8/0x480 fs/reiserfs/namei.c:368
 __lookup_slow+0x29d/0x3f0 fs/namei.c:1698
 lookup_one_len+0x19d/0x2d0 fs/namei.c:2748
 open_xa_dir+0x464/0x6f0 fs/reiserfs/xattr.c:162
 xattr_lookup+0x22/0x2a0 fs/reiserfs/xattr.c:395
 reiserfs_xattr_set_handle+0x100/0xcd0 fs/reiserfs/xattr.c:533
 reiserfs_xattr_set+0x467/0x590 fs/reiserfs/xattr.c:633
 __vfs_setxattr+0x3e0/0x420 fs/xattr.c:182
 __vfs_setxattr_noperm+0x129/0x5e0 fs/xattr.c:216
 vfs_setxattr+0x167/0x2e0 fs/xattr.c:309
 do_setxattr fs/xattr.c:594 [inline]
 setxattr+0x346/0x360 fs/xattr.c:617
 __do_sys_fsetxattr fs/xattr.c:673 [inline]
 __se_sys_fsetxattr+0x15e/0x1d0 fs/xattr.c:662
 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: 0033:0x7f74f8f9c819
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:00007f74f71d5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000be
RAX: ffffffffffffffda RBX: 00007f74f9216090 RCX: 00007f74f8f9c819
RDX: 0000000000000000 RSI: 0000200000000340 RDI: 0000000000000007
RBP: 00007f74f9032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f74f9216128 R14: 00007f74f9216090 R15: 00007ffd5d44c478
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00012e9300 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x4ba4c
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 5210, tgid 5210 (syz.5.210), ts 125388281979, free_ts 126518830499
 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+0xe/0x30 mm/page_alloc.c:5689
 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1589 [inline]
 shmem_alloc_and_acct_folio+0x463/0xbc0 mm/shmem.c:1613
 shmem_get_folio_gfp+0x1361/0x3400 mm/shmem.c:1941
 shmem_get_folio mm/shmem.c:2072 [inline]
 shmem_write_begin+0xee/0x3f0 mm/shmem.c:2556
 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
 __kernel_write_iter+0x285/0x650 fs/read_write.c:517
 dump_emit_page fs/coredump.c:950 [inline]
 dump_user_range+0x412/0x850 fs/coredump.c:977
 elf_core_dump+0x30a6/0x35d0 fs/binfmt_elf.c:2354
 do_coredump+0x165b/0x22f0 fs/coredump.c:824
 get_signal+0x10aa/0x1350 kernel/signal.c:2857
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
 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

Memory state around the buggy address:
 ffff88804ba4ce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804ba4cf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804ba4cf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88804ba4d000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804ba4d080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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