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BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x631/0xab0
Read of size 72 at addr ffff8880612fffe8 by task syz-executor.2/6152

CPU: 1 PID: 6152 Comm: syz-executor.2 Not tainted 6.1.34-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 kasan_check_range+0x27f/0x290 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 leaf_paste_in_buffer+0x631/0xab0
 leaf_copy_dir_entries+0x71a/0xc60 fs/reiserfs/lbalance.c:108
 leaf_copy_boundary_item+0xbbe/0x21b0 fs/reiserfs/lbalance.c:168
 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_when_delete_left fs/reiserfs/do_balan.c:194 [inline]
 balance_leaf_when_delete fs/reiserfs/do_balan.c:272 [inline]
 balance_leaf+0x228e/0x12510 fs/reiserfs/do_balan.c:1393
 do_balance+0x309/0x8f0 fs/reiserfs/do_balan.c:1888
 reiserfs_cut_from_item+0x1945/0x2580 fs/reiserfs/stree.c:1838
 reiserfs_do_truncate+0xa12/0x15b0 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x4d6/0x810 fs/reiserfs/inode.c:2310
 reiserfs_setattr+0xc57/0x11c0 fs/reiserfs/inode.c:3395
 notify_change+0xdcd/0x1080 fs/attr.c:482
 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:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f3dfe08c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3dfed13168 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f3dfe1ac050 RCX: 00007f3dfe08c389
RDX: 0000000000000000 RSI: 0000000000000e00 RDI: 0000000000000005
RBP: 00007f3dfe0d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd72109a6f R14: 00007f3dfed13300 R15: 0000000000022000
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000184bfc0 refcount:2 mapcount:0 mapping:ffff888012915ff8 index:0x214 pfn:0x612ff
memcg:ffff8880791dc000
aops:def_blk_aops ino:700002
flags: 0xfff30000002052(referenced|lru|workingset|private|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff30000002052 ffffea0001807b48 ffffea0001847cc8 ffff888012915ff8
raw: 0000000000000214 ffff888074f24cb0 00000002ffffffff ffff8880791dc000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x148c48(GFP_NOFS|__GFP_NOFAIL|__GFP_COMP|__GFP_HARDWALL|__GFP_MOVABLE), pid 6152, tgid 6136 (syz-executor.2), ts 1195154452969, free_ts 1195153783852
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2533
 prep_new_page mm/page_alloc.c:2540 [inline]
 get_page_from_freelist+0x32ed/0x3480 mm/page_alloc.c:4292
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5559
 folio_alloc+0x1a/0x50 mm/mempolicy.c:2290
 filemap_alloc_folio+0xda/0x4f0 mm/filemap.c:971
 __filemap_get_folio+0x711/0xe30 mm/filemap.c:1965
 pagecache_get_page+0x28/0x250 mm/folio-compat.c:110
 find_or_create_page include/linux/pagemap.h:613 [inline]
 grow_dev_page fs/buffer.c:946 [inline]
 grow_buffers fs/buffer.c:1011 [inline]
 __getblk_slow fs/buffer.c:1038 [inline]
 __getblk_gfp+0x211/0xa20 fs/buffer.c:1333
 sb_getblk include/linux/buffer_head.h:356 [inline]
 get_empty_nodes+0x8c1/0xd70 fs/reiserfs/fix_node.c:890
 fix_nodes+0x2615/0x8c70 fs/reiserfs/fix_node.c:2662
 reiserfs_insert_item+0xa7a/0xcb0 fs/reiserfs/stree.c:2240
 indirect2direct+0x695/0xc00 fs/reiserfs/tail_conversion.c:283
 maybe_indirect_to_direct fs/reiserfs/stree.c:1587 [inline]
 reiserfs_cut_from_item+0xba3/0x2580 fs/reiserfs/stree.c:1694
 reiserfs_do_truncate+0xa12/0x15b0 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x4d6/0x810 fs/reiserfs/inode.c:2310
 reiserfs_setattr+0xc57/0x11c0 fs/reiserfs/inode.c:3395
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1460 [inline]
 free_pcp_prepare mm/page_alloc.c:1510 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3388
 free_unref_page_list+0x107/0x810 mm/page_alloc.c:3530
 release_pages+0x2836/0x2b40 mm/swap.c:1055
 __pagevec_release+0x80/0xf0 mm/swap.c:1075
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 truncate_inode_pages_range+0x48a/0x1340 mm/truncate.c:373
 truncate_inode_pages mm/truncate.c:452 [inline]
 truncate_pagecache mm/truncate.c:753 [inline]
 truncate_setsize+0xcb/0xf0 mm/truncate.c:778
 reiserfs_setattr+0xc4a/0x11c0 fs/reiserfs/inode.c:3394
 notify_change+0xdcd/0x1080 fs/attr.c:482
 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:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff8880612fff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880612fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888061300000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888061300080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888061300100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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