==================================================================
BUG: KASAN: use-after-free in leaf_paste_entries+0xa9c/0xb10 fs/reiserfs/lbalance.c:1351
Read of size 2 at addr ffff0000f4018e98 by task syz.1.424/6608

CPU: 0 PID: 6608 Comm: syz.1.424 Not tainted 6.1.114-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x174/0x4c0 mm/kasan/report.c:395
 kasan_report+0xd4/0x130 mm/kasan/report.c:495
 __asan_report_load_n_noabort+0x28/0x34 mm/kasan/report_generic.c:361
 leaf_paste_entries+0xa9c/0xb10 fs/reiserfs/lbalance.c:1351
 leaf_copy_dir_entries+0x5dc/0xa04 fs/reiserfs/lbalance.c:119
 leaf_copy_boundary_item+0x8c4/0x1a34 fs/reiserfs/lbalance.c:168
 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_when_delete_left fs/reiserfs/do_balan.c:194 [inline]
 balance_leaf_when_delete fs/reiserfs/do_balan.c:272 [inline]
 balance_leaf+0x2a70/0xe860 fs/reiserfs/do_balan.c:1393
 do_balance+0x27c/0x788 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x12b8/0x1c98 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0x89c/0x11c8 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x510/0xb1c fs/reiserfs/inode.c:2310
 reiserfs_setattr+0xb58/0x101c fs/reiserfs/inode.c:3395
 notify_change+0xb58/0xe1c fs/attr.c:499
 do_truncate+0x1c0/0x28c fs/open.c:65
 handle_truncate fs/namei.c:3285 [inline]
 do_open fs/namei.c:3630 [inline]
 path_openat+0x1fa0/0x2548 fs/namei.c:3783
 do_filp_open+0x1bc/0x3cc fs/namei.c:3810
 do_sys_openat2+0x128/0x3e0 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]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1345
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x168 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:00000000a743a5ca refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x134018
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000f4018d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f4018e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000f4018e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff0000f4018f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f4018f80: 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 ffff0000f33c0ff0
KASAN: maybe wild-memory-access in range [0xfffc000799e07f80-0xfffc000799e07f87]
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
swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000001ab36e000
[ffff0000f33c0ff0] pgd=180000023fff8003, p4d=180000023fff8003, pud=180000023f414003, pmd=180000023f27a003, pte=00600001333c0787