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BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x1b8/0xab0 fs/reiserfs/lbalance.c:1017
Write of size 3936 at addr ffff88804ef09140 by task syz.5.1224/10761

CPU: 1 PID: 10761 Comm: syz.5.1224 Not tainted 6.1.123-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:427
 kasan_report+0x136/0x160 mm/kasan/report.c:531
 kasan_check_range+0x27f/0x290 mm/kasan/generic.c:189
 memmove+0x3c/0x60 mm/kasan/shadow.c:55
 leaf_paste_in_buffer+0x1b8/0xab0 fs/reiserfs/lbalance.c:1017
 leaf_copy_boundary_item+0xcbf/0x21b0 fs/reiserfs/lbalance.c:199
 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline]
 leaf_move_items+0xcd0/0x28a0 fs/reiserfs/lbalance.c:726
 leaf_shift_left+0xba/0x430 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+0x3071/0x12510 fs/reiserfs/do_balan.c:1409
 do_balance+0x309/0x8f0 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x73b/0x880 fs/reiserfs/stree.c:2159
 reiserfs_get_block+0x2259/0x5150 fs/reiserfs/inode.c:1069
 __block_write_begin_int+0x544/0x1a30 fs/buffer.c:1991
 reiserfs_write_begin+0x249/0x510 fs/reiserfs/inode.c:2775
 generic_cont_expand_simple+0x187/0x2a0 fs/buffer.c:2347
 reiserfs_setattr+0x606/0x11c0 fs/reiserfs/inode.c:3305
 notify_change+0xce3/0xfc0 fs/attr.c:499
 do_truncate+0x21c/0x300 fs/open.c:65
 do_sys_ftruncate+0x2e2/0x380 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f430a585d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f430b454038 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f430a776080 RCX: 00007f430a585d29
RDX: 0000000000000000 RSI: 0000000002000009 RDI: 0000000000000005
RBP: 00007f430a601b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f430a776080 R15: 00007ffd18c1fa68
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00013bc240 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x4ef09
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00014511c8 ffffea00013e5788 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 10758, tgid 10758 (dhcpcd-run-hook), ts 364063839892, free_ts 364071046358
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4328
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5605
 __folio_alloc+0xf/0x30 mm/page_alloc.c:5637
 vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243
 alloc_page_vma include/linux/gfp.h:284 [inline]
 wp_page_copy+0x291/0x18c0 mm/memory.c:3151
 handle_pte_fault mm/memory.c:5047 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x2525/0x5340 mm/memory.c:5292
 do_user_addr_fault arch/x86/mm/fault.c:1340 [inline]
 handle_page_fault arch/x86/mm/fault.c:1431 [inline]
 exc_page_fault+0x26f/0x620 arch/x86/mm/fault.c:1487
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x12a6/0x15b0 mm/page_alloc.c:3384
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3525
 release_pages+0x24c4/0x27a0 mm/swap.c:1035
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261
 tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361
 exit_mmap+0x3b3/0x980 mm/mmap.c:3250
 __mmput+0x115/0x3c0 kernel/fork.c:1200
 exit_mm+0x226/0x300 kernel/exit.c:565
 do_exit+0x9f1/0x26a0 kernel/exit.c:858
 do_group_exit+0x202/0x2b0 kernel/exit.c:1021
 __do_sys_exit_group kernel/exit.c:1032 [inline]
 __se_sys_exit_group kernel/exit.c:1030 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1030
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88804ef09000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804ef09080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804ef09100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88804ef09180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804ef09200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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