==================================================================
BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x1a8/0x9f0 fs/reiserfs/lbalance.c:1017
Write of size 3936 at addr ffff0000eb728140 by task syz.1.133/4998

CPU: 1 PID: 4998 Comm: syz.1.133 Not tainted 5.15.176-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x174/0x1e4 mm/kasan/report.c:451
 kasan_check_range+0x274/0x2b4 mm/kasan/generic.c:189
 memmove+0xb4/0xe8 mm/kasan/shadow.c:55
 leaf_paste_in_buffer+0x1a8/0x9f0 fs/reiserfs/lbalance.c:1017
 leaf_copy_boundary_item+0x96c/0x1a34 fs/reiserfs/lbalance.c:199
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0xa0c/0x1f7c fs/reiserfs/lbalance.c:726
 leaf_shift_left+0xc8/0x39c 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+0x41c0/0xe860 fs/reiserfs/do_balan.c:1409
 do_balance+0x27c/0x790 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x630/0x744 fs/reiserfs/stree.c:2159
 reiserfs_get_block+0x1820/0x3fd0 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x3ec/0x1608 fs/buffer.c:2012
 __block_write_begin+0x40/0x54 fs/buffer.c:2062
 reiserfs_write_begin+0x3c8/0x654 fs/reiserfs/inode.c:2790
 generic_perform_write+0x24c/0x520 mm/filemap.c:3785
 __generic_file_write_iter+0x230/0x454 mm/filemap.c:3912
 generic_file_write_iter+0xb4/0x1b8 mm/filemap.c:3944
 __kernel_write+0x488/0x8b8 fs/read_write.c:539
 __dump_emit+0x200/0x338 fs/coredump.c:875
 dump_emit+0x288/0x36c fs/coredump.c:912
 elf_core_dump+0x2598/0x3640 fs/binfmt_elf.c:2237
 do_coredump+0x12c8/0x2890 fs/coredump.c:826
 get_signal+0x3dc/0x1550 kernel/signal.c:2886
 do_signal arch/arm64/kernel/signal.c:890 [inline]
 do_notify_resume+0x320/0x32b8 arch/arm64/kernel/signal.c:943
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
 el0_da+0x118/0x20c arch/arm64/kernel/entry-common.c:495
 el0t_64_sync_handler+0xc0/0xe4 arch/arm64/kernel/entry-common.c:629
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the page:
page:00000000803d25b4 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12b728
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003a9bec8 fffffc0003aef508 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000eb728000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000eb728080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000eb728100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff0000eb728180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000eb728200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Unable to handle kernel write to read-only memory at virtual address ffff0000f00b9000
Mem abort info:
  ESR = 0x000000009600004f
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x0f: level 3 permission fault
Data abort info:
  ISV = 0, ISS = 0x0000004f
  CM = 0, WnR = 1