REISERFS (device loop0): Using r5 hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x694/0xa40 fs/reiserfs/lbalance.c:1037
Write of size 420 at addr ffff0000f3802e5c by task syz.0.18/4482

CPU: 0 PID: 4482 Comm: syz.0.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x258/0x290 mm/kasan/generic.c:189
 memcpy+0x60/0x90 mm/kasan/shadow.c:66
 leaf_paste_in_buffer+0x694/0xa40 fs/reiserfs/lbalance.c:1037
 leaf_copy_boundary_item+0x928/0x19f4 fs/reiserfs/lbalance.c:199
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0x6c8/0xbd8 fs/reiserfs/lbalance.c:726
 leaf_shift_left+0xc4/0x3ac 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+0x3db8/0xdee0 fs/reiserfs/do_balan.c:1409
 do_balance+0x270/0x794 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x640/0x6e8 fs/reiserfs/stree.c:2159
 reiserfs_get_block+0x1538/0x3860 fs/reiserfs/inode.c:1069
 __block_write_begin_int+0x3d8/0x13c0 fs/buffer.c:1991
 __block_write_begin+0x7c/0xa0 fs/buffer.c:2041
 reiserfs_write_begin+0x328/0x718 fs/reiserfs/inode.c:2775
 generic_perform_write+0x240/0x508 mm/filemap.c:3862
 __generic_file_write_iter+0x130/0x250 mm/filemap.c:3960
 generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_write+0x520/0x93c fs/read_write.c:861
 vfs_writev fs/read_write.c:934 [inline]
 do_pwritev+0x1e8/0x338 fs/read_write.c:1031
 __do_sys_pwritev2 fs/read_write.c:1090 [inline]
 __se_sys_pwritev2 fs/read_write.c:1081 [inline]
 __arm64_sys_pwritev2+0xdc/0x110 fs/read_write.c:1081
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:0000000020734479 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x133802
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 ffff0001fea6e578 ffff0001fea6e578 0000000000000000
raw: 0000000000000000 0000000000000001 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000f3802d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f3802d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000f3802e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                    ^
 ffff0000f3802e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f3802f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
REISERFS warning: reiserfs-5090 is_tree_node: node level 0 does not match to the expected one 2
REISERFS error (device loop0): vs-5150 search_by_key: invalid format found in block 531. Fsck?
REISERFS (device loop0): Remounting filesystem read-only
REISERFS error (device loop0): vs-13050 reiserfs_update_sd_size: i/o failure occurred trying to update [2 2 0x0 SD] stat data