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BUG: KASAN: use-after-free in leaf_paste_entries+0x374/0x944 fs/reiserfs/lbalance.c:1362
Read of size 2 at addr ffff0000e585b008 by task syz-executor345/4341

CPU: 0 PID: 4341 Comm: syz-executor345 Not tainted 5.15.171-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
 __asan_report_load_n_noabort+0x40/0x4c mm/kasan/report_generic.c:319
 leaf_paste_entries+0x374/0x944 fs/reiserfs/lbalance.c:1362
 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/0x790 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x12b8/0x1c84 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0x89c/0x11c8 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x3ac/0x6f0 fs/reiserfs/inode.c:2318
 reiserfs_setattr+0x8e8/0xd94 fs/reiserfs/inode.c:3409
 notify_change+0xa34/0xcf8 fs/attr.c:505
 do_truncate+0x1c0/0x28c fs/open.c:65
 handle_truncate fs/namei.c:3265 [inline]
 do_open fs/namei.c:3612 [inline]
 path_openat+0x20c4/0x26cc fs/namei.c:3742
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3769
 do_sys_openat2+0x128/0x3e0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1280
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the page:
page:0000000006e7c864 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x12585b
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003a12048 fffffc0003955708 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000e585af00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000e585af80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000e585b000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff0000e585b080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000e585b100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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