================================================================== BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x6a1/0xbd0 fs/reiserfs/lbalance.c:-1 Read of size 48 at addr ffff8880707a0ff0 by task syz.0.31/6770 CPU: 0 PID: 6770 Comm: syz.0.31 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xac/0x220 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x288/0x290 mm/kasan/generic.c:187 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105 leaf_paste_in_buffer+0x6a1/0xbd0 fs/reiserfs/lbalance.c:-1 leaf_copy_dir_entries+0x5e7/0x990 fs/reiserfs/lbalance.c:108 leaf_copy_boundary_item+0xb90/0x2180 fs/reiserfs/lbalance.c:168 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline] leaf_move_items+0x8b5/0xe90 fs/reiserfs/lbalance.c:726 balance_leaf_when_delete_left fs/reiserfs/do_balan.c:167 [inline] balance_leaf_when_delete fs/reiserfs/do_balan.c:272 [inline] balance_leaf+0xc257/0x10da0 fs/reiserfs/do_balan.c:1393 do_balance+0x2fe/0x940 fs/reiserfs/do_balan.c:1888 reiserfs_cut_from_item+0x13b2/0x1f10 fs/reiserfs/stree.c:1836 reiserfs_do_truncate+0xa3d/0x1340 fs/reiserfs/stree.c:1971 reiserfs_truncate_file+0x37a/0x7c0 fs/reiserfs/inode.c:2306 reiserfs_setattr+0xc0c/0x11a0 fs/reiserfs/inode.c:3392 notify_change+0xb0d/0xe10 fs/attr.c:499 do_truncate+0x19b/0x220 fs/open.c:66 handle_truncate fs/namei.c:3291 [inline] do_open fs/namei.c:3636 [inline] path_openat+0x298c/0x3190 fs/namei.c:3789 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419 do_sys_open fs/open.c:1434 [inline] __do_sys_openat fs/open.c:1450 [inline] __se_sys_openat fs/open.c:1445 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1445 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4a1038ebe9 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:00007f4a0f9dd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f4a105b6180 RCX: 00007f4a1038ebe9 RDX: 0000000000000300 RSI: 0000200000000080 RDI: ffffffffffffff9c RBP: 00007f4a10411e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4a105b6218 R14: 00007f4a105b6180 R15: 00007ffc56bd3a78 The buggy address belongs to the physical page: page:ffffea0001c1e800 refcount:2 mapcount:0 mapping:ffff88801fddc1f8 index:0x343 pfn:0x707a0 memcg:ffff888078818000 aops:def_blk_aops ino:700000 flags: 0xfff58000008234(referenced|dirty|lru|workingset|private|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff58000008234 ffffea0001bd2dc8 ffffea0001c17ec8 ffff88801fddc1f8 raw: 0000000000000343 ffff88805f685658 00000002ffffffff ffff888078818000 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 6769, tgid 6766 (syz.0.31), ts 130679586528, free_ts 130315448996 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554 prep_new_page mm/page_alloc.c:1561 [inline] get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457 folio_alloc+0x1e/0x30 mm/mempolicy.c:2291 filemap_alloc_folio+0xdf/0x470 mm/filemap.c:1004 __filemap_get_folio+0x3ee/0xbc0 mm/filemap.c:1962 grow_dev_page fs/buffer.c:1058 [inline] grow_buffers fs/buffer.c:1118 [inline] __getblk_slow fs/buffer.c:1145 [inline] __getblk_gfp+0x223/0x660 fs/buffer.c:1439 sb_getblk include/linux/buffer_head.h:344 [inline] get_empty_nodes+0x515/0x8c0 fs/reiserfs/fix_node.c:890 fix_nodes+0x1e52/0x82e0 fs/reiserfs/fix_node.c:2663 reiserfs_paste_into_item+0x5ce/0x7f0 fs/reiserfs/stree.c:2128 reiserfs_get_block+0x1bd3/0x3ed0 fs/reiserfs/inode.c:1069 __block_write_begin_int+0x566/0x1ad0 fs/buffer.c:2124 reiserfs_write_begin+0x20a/0x4c0 fs/reiserfs/inode.c:2771 generic_perform_write+0x2fb/0x5b0 mm/filemap.c:4016 generic_file_write_iter+0xaf/0x2e0 mm/filemap.c:4137 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x79a/0xc70 fs/read_write.c:860 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1154 [inline] free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475 release_pages+0x1fa0/0x2220 mm/swap.c:1022 __folio_batch_release+0x71/0xe0 mm/swap.c:1042 folio_batch_release include/linux/pagevec.h:83 [inline] truncate_inode_pages_range+0x358/0xf00 mm/truncate.c:371 reiserfs_evict_inode+0x15a/0x490 fs/reiserfs/inode.c:42 evict+0x486/0x870 fs/inode.c:705 dispose_list fs/inode.c:738 [inline] evict_inodes+0x5fe/0x690 fs/inode.c:792 generic_shutdown_super+0x97/0x2b0 fs/super.c:672 kill_block_super+0x44/0x90 fs/super.c:1660 deactivate_locked_super+0x97/0x100 fs/super.c:481 cleanup_mnt+0x429/0x4c0 fs/namespace.c:1250 task_work_run+0x1ce/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 Memory state around the buggy address: ffff8880707a0f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880707a0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880707a1000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8880707a1080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880707a1100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================