REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
REISERFS warning (device loop0): vs-13060 reiserfs_update_sd_size: stat data of object [2 6 0x0 SD] (nlink == 1) not found (pos 1)
==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x1c8/0xab0 fs/reiserfs/lbalance.c:1017
Write of size 3936 at addr ffff88806c33c140 by task syz.0.31/5296

CPU: 0 PID: 5296 Comm: syz.0.31 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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+0x3c/0x60 mm/kasan/shadow.c:55
 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_shift fs/reiserfs/do_balan.c:458 [inline]
 balance_leaf_paste_left fs/reiserfs/do_balan.c:592 [inline]
 balance_leaf_left fs/reiserfs/do_balan.c:613 [inline]
 balance_leaf+0x2c05/0x10e60 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
 do_iter_readv_writev+0x497/0x600 fs/read_write.c:-1
 do_iter_write+0x205/0x7b0 fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_pwritev+0x204/0x340 fs/read_write.c:1025
 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: 0033:0x7f60f0bbfb59
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:00007f60efe48048 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007f60f0d4ff60 RCX: 00007f60f0bbfb59
RDX: 0000000000000001 RSI: 0000000020000100 RDI: 0000000000000006
RBP: 00007f60f0c2ee5d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f60f0d4ff60 R15: 00007fffa95976c8
 </TASK>

The buggy address belongs to the page:
page:ffffea0001b0cf00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6c33c
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001b0d008 ffffea0001854748 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 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 5293, ts 107234824903, free_ts 107792549097
 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:5474
 __page_cache_alloc+0xd2/0x3f0 mm/filemap.c:1022
 pagecache_get_page+0x986/0xef0 mm/filemap.c:1940
 find_or_create_page include/linux/pagemap.h:420 [inline]
 grow_dev_page fs/buffer.c:949 [inline]
 grow_buffers fs/buffer.c:1014 [inline]
 __getblk_slow fs/buffer.c:1041 [inline]
 __getblk_gfp+0x249/0xb70 fs/buffer.c:1336
 __getblk include/linux/buffer_head.h:416 [inline]
 reiserfs_breada fs/reiserfs/journal.c:2335 [inline]
 journal_read+0x7ff/0x3800 fs/reiserfs/journal.c:2447
 journal_init+0x1961/0x2360 fs/reiserfs/journal.c:2895
 reiserfs_fill_super+0xc7f/0x23e0 fs/reiserfs/super.c:2026
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3014
 do_mount fs/namespace.c:3357 [inline]
 __do_sys_mount fs/namespace.c:3565 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3542
 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
 __pagevec_release+0x6d/0xe0 mm/swap.c:983
 pagevec_release include/linux/pagevec.h:81 [inline]
 truncate_inode_pages_range+0x2f3/0xef0 mm/truncate.c:329
 kill_bdev block/bdev.c:77 [inline]
 blkdev_flush_mapping+0x182/0x340 block/bdev.c:659
 blkdev_put_whole block/bdev.c:690 [inline]
 blkdev_put+0x4d1/0x7d0 block/bdev.c:957
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x418/0x4d0 fs/namespace.c:1139
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 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
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88806c33c000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806c33c080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806c33c100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88806c33c180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806c33c200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================