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BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x1c8/0xa14 fs/reiserfs/lbalance.c:1017
Write of size 308 at addr ffff0000f9f7ff60 by task syz.1.130/4867

CPU: 0 PID: 4867 Comm: syz.1.130 Not tainted 6.1.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/18/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 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+0xf8/0x160 lib/dump_stack.c:106
 print_address_description+0x88/0x200 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:418
 kasan_report+0xa8/0x100 mm/kasan/report.c:522
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x260/0x2a0 mm/kasan/generic.c:189
 memmove+0x60/0x90 mm/kasan/shadow.c:55
 leaf_paste_in_buffer+0x1c8/0xa14 fs/reiserfs/lbalance.c:1017
 balance_leaf_paste_left_shift fs/reiserfs/do_balan.c:465 [inline]
 balance_leaf_paste_left fs/reiserfs/do_balan.c:592 [inline]
 balance_leaf_left fs/reiserfs/do_balan.c:613 [inline]
 balance_leaf+0x8b4c/0xd2f4 fs/reiserfs/do_balan.c:1409
 do_balance+0x260/0x774 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x5b4/0x6d0 fs/reiserfs/stree.c:2159
 reiserfs_get_block+0x1444/0x3524 fs/reiserfs/inode.c:1069
 __block_write_begin_int+0x34c/0x13b8 fs/buffer.c:1991
 __block_write_begin+0x7c/0xa0 fs/buffer.c:2041
 reiserfs_write_begin+0x328/0x71c fs/reiserfs/inode.c:2775
 generic_cont_expand_simple+0x12c/0x1fc fs/buffer.c:2347
 reiserfs_setattr+0x564/0xf7c fs/reiserfs/inode.c:3305
 notify_change+0xb0c/0xdcc fs/attr.c:499
 do_truncate+0x178/0x1f0 fs/open.c:65
 vfs_truncate+0x23c/0x2b0 fs/open.c:111
 do_sys_truncate+0xe8/0x1b0 fs/open.c:134
 __do_sys_truncate fs/open.c:146 [inline]
 __se_sys_truncate fs/open.c:144 [inline]
 __arm64_sys_truncate+0x5c/0x70 fs/open.c:144
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 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:000000003da0e16d refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x139f7f
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:
 ffff0000f9f7fe00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f9f7fe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000f9f7ff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                       ^
 ffff0000f9f7ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f9f80000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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