REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using r5 hash to sort names
REISERFS (device loop0): using 3.5.x disk format
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x617/0xaa0 fs/reiserfs/lbalance.c:-1
Read of size 48 at addr ffff88806a050ff0 by task syz.0.17/4416

CPU: 0 PID: 4416 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e 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+0x27b/0x290 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x617/0xaa0 fs/reiserfs/lbalance.c:-1
 leaf_copy_dir_entries+0x56c/0x8f0 fs/reiserfs/lbalance.c:108
 leaf_copy_boundary_item+0xb8c/0x2190 fs/reiserfs/lbalance.c:168
 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_left fs/reiserfs/do_balan.c:616 [inline]
 balance_leaf+0x13db/0x10e60 fs/reiserfs/do_balan.c:1409
 do_balance+0x2fa/0x930 fs/reiserfs/do_balan.c:1888
 reiserfs_insert_item+0xa4f/0xbb0 fs/reiserfs/stree.c:2261
 add_save_link+0x366/0x5c0 fs/reiserfs/super.c:495
 reiserfs_truncate_file+0x354/0x7c0 fs/reiserfs/inode.c:2309
 reiserfs_setattr+0xcae/0x1240 fs/reiserfs/inode.c:3395
 notify_change+0xc74/0xf40 fs/attr.c:499
 do_truncate+0x197/0x220 fs/open.c:65
 handle_truncate fs/namei.c:3285 [inline]
 do_open fs/namei.c:3630 [inline]
 path_openat+0x27f2/0x2e70 fs/namei.c:3783
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
 do_sys_openat2+0x142/0x490 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_openat fs/open.c:1350 [inline]
 __se_sys_openat fs/open.c:1345 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1345
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f64d738eba9
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:00007ffe6c2256a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f64d75d5fa0 RCX: 00007f64d738eba9
RDX: 000000000000275a RSI: 0000200000000200 RDI: 0000000000000004
RBP: 00007f64d7411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f64d75d5fa0 R14: 00007f64d75d5fa0 R15: 0000000000000004
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001a81400 refcount:2 mapcount:0 mapping:ffff8880178854f8 index:0x214 pfn:0x6a050
memcg:ffff8880741dc000
aops:def_blk_aops ino:700000
flags: 0xfff58000002052(referenced|lru|workingset|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff58000002052 ffffea00017b4348 ffffea0001a87d48 ffff8880178854f8
raw: 0000000000000214 ffff8880712c5488 00000002ffffffff ffff8880741dc000
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 4416, tgid 4416 (syz.0.17), ts 107826486719, free_ts 107825642091
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
 folio_alloc+0x1c/0x60 mm/mempolicy.c:2292
 filemap_alloc_folio+0xdb/0x460 mm/filemap.c:999
 __filemap_get_folio+0x697/0xdd0 mm/filemap.c:1993
 pagecache_get_page+0x26/0x250 mm/folio-compat.c:110
 find_or_create_page include/linux/pagemap.h:646 [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
 sb_getblk include/linux/buffer_head.h:356 [inline]
 get_empty_nodes+0x511/0x8c0 fs/reiserfs/fix_node.c:890
 fix_nodes+0x1e69/0x82d0 fs/reiserfs/fix_node.c:2662
 reiserfs_insert_item+0x973/0xbb0 fs/reiserfs/stree.c:2240
 indirect2direct+0x592/0x9c0 fs/reiserfs/tail_conversion.c:283
 maybe_indirect_to_direct fs/reiserfs/stree.c:1587 [inline]
 reiserfs_cut_from_item+0x76a/0x1ef0 fs/reiserfs/stree.c:1694
 reiserfs_do_truncate+0xa90/0x13e0 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x376/0x7c0 fs/reiserfs/inode.c:2310
 reiserfs_setattr+0xcae/0x1240 fs/reiserfs/inode.c:3395
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525
 release_pages+0x1f92/0x2200 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]
 truncate_inode_pages_range+0x2f6/0xff0 mm/truncate.c:372
 truncate_inode_pages mm/truncate.c:451 [inline]
 truncate_pagecache mm/truncate.c:751 [inline]
 truncate_setsize+0xb9/0xe0 mm/truncate.c:776
 reiserfs_setattr+0xca1/0x1240 fs/reiserfs/inode.c:3394
 notify_change+0xc74/0xf40 fs/attr.c:499
 do_truncate+0x197/0x220 fs/open.c:65
 do_sys_ftruncate+0x312/0x3c0 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88806a050f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88806a050f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806a051000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88806a051080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806a051100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================