REISERFS warning (device loop1): vs-13060 reiserfs_update_sd_size: stat data of object [2 5 0x0 SD] (nlink == 1) not found (pos 1)
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BUG: KASAN: out-of-bounds in leaf_paste_in_buffer+0x1c8/0xab0 fs/reiserfs/lbalance.c:1017
Read of size 18446744073709493643 at addr ffff88805cc48275 by task syz.1.9/4324

CPU: 0 PID: 4324 Comm: syz.1.9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x27b/0x290 mm/kasan/generic.c:189
 memmove+0x25/0x60 mm/kasan/shadow.c:54
 leaf_paste_in_buffer+0x1c8/0xab0 fs/reiserfs/lbalance.c:1017
 leaf_copy_boundary_item+0xc75/0x2190 fs/reiserfs/lbalance.c:199
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0x84a/0xde0 fs/reiserfs/lbalance.c:726
 leaf_shift_left+0xb9/0x450 fs/reiserfs/lbalance.c:750
 balance_leaf_paste_left_whole fs/reiserfs/do_balan.c:560 [inline]
 balance_leaf_paste_left fs/reiserfs/do_balan.c:594 [inline]
 balance_leaf_left fs/reiserfs/do_balan.c:613 [inline]
 balance_leaf+0x2fb7/0x10e60 fs/reiserfs/do_balan.c:1409
 do_balance+0x2fa/0x930 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x69b/0x7e0 fs/reiserfs/stree.c:2159
 reiserfs_get_block+0x1bde/0x4100 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012
 reiserfs_write_begin+0x34b/0x810 fs/reiserfs/inode.c:2790
 generic_perform_write+0x2aa/0x530 mm/filemap.c:3785
 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912
 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944
 call_write_iter include/linux/fs.h:2173 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x712/0xd00 fs/read_write.c:594
 ksys_pwrite64 fs/read_write.c:701 [inline]
 __do_sys_pwrite64 fs/read_write.c:711 [inline]
 __se_sys_pwrite64 fs/read_write.c:708 [inline]
 __x64_sys_pwrite64+0x194/0x220 fs/read_write.c:708
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f374201e749
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:00007f3740285038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f3742274fa0 RCX: 00007f374201e749
RDX: 0000000000000001 RSI: 000020000001f900 RDI: 0000000000000007
RBP: 00007f37420a2f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000c63 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3742275038 R14: 00007f3742274fa0 R15: 00007ffd1d671ca8
 </TASK>

The buggy address belongs to the page:
page:ffffea0001731200 refcount:1 mapcount:0 mapping:ffff888076182ed8 index:0xd57 pfn:0x5cc48
memcg:ffff888079820000
aops:shmem_aops ino:2 dentry name:"memfd:syzkaller"
flags: 0xfff0000008001e(referenced|uptodate|dirty|lru|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff0000008001e ffffea00017311c8 ffffea0001731248 ffff888076182ed8
raw: 0000000000000d57 0000000000000000 00000001ffffffff ffff888079820000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 4304, ts 84452631191, free_ts 84346473518
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487
 alloc_pages_vma+0x393/0x7c0 mm/mempolicy.c:2146
 shmem_alloc_page mm/shmem.c:1586 [inline]
 shmem_alloc_and_acct_page+0x427/0xb70 mm/shmem.c:1611
 shmem_getpage_gfp+0x14f4/0x2d40 mm/shmem.c:1906
 shmem_getpage mm/shmem.c:151 [inline]
 shmem_write_begin+0xcd/0x1a0 mm/shmem.c:2474
 generic_perform_write+0x2aa/0x530 mm/filemap.c:3785
 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912
 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944
 call_write_iter include/linux/fs.h:2173 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x712/0xd00 fs/read_write.c:594
 ksys_write+0x14d/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page_list+0x122/0x7e0 mm/page_alloc.c:3433
 release_pages+0x184b/0x1bb0 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu+0xc5/0x170 mm/mmu_gather.c:247
 zap_pte_range mm/memory.c:1456 [inline]
 zap_pmd_range mm/memory.c:1505 [inline]
 zap_pud_range mm/memory.c:1534 [inline]
 zap_p4d_range mm/memory.c:1555 [inline]
 unmap_page_range+0x2096/0x2520 mm/memory.c:1576
 unmap_vmas+0x11b/0x230 mm/memory.c:1653
 exit_mmap+0x38f/0x5f0 mm/mmap.c:3216
 __mmput+0x115/0x3b0 kernel/fork.c:1127
 exit_mm+0x567/0x6c0 kernel/exit.c:550
 do_exit+0x5a1/0x20a0 kernel/exit.c:870
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307

Memory state around the buggy address:
 ffff88805cc48100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88805cc48180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805cc48200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                             ^
 ffff88805cc48280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88805cc48300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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