================================================================== BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x6a1/0xbd0 fs/reiserfs/lbalance.c:-1 Read of size 48 at addr ffff88805b8deff0 by task syz.2.2/5891 CPU: 1 PID: 5891 Comm: syz.2.2 Not tainted 6.6.102-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 vfs_truncate+0x266/0x300 fs/open.c:112 do_sys_truncate+0xe0/0x1a0 fs/open.c:135 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: 0033:0x7f6cc218ebe9 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:00007f6cc2f7f038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c RAX: ffffffffffffffda RBX: 00007f6cc23b6090 RCX: 00007f6cc218ebe9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00002000000000c0 RBP: 00007f6cc2211e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6cc23b6128 R14: 00007f6cc23b6090 R15: 00007ffef31cdb78 The buggy address belongs to the physical page: page:ffffea00016e3780 refcount:2 mapcount:0 mapping:ffff88801fc713f8 index:0x234 pfn:0x5b8de memcg:ffff88805d440000 aops:def_blk_aops ino:700002 flags: 0xfff58000008224(referenced|lru|workingset|private|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff58000008224 ffffea00016e3748 ffffea0001b0a1c8 ffff88801fc713f8 raw: 0000000000000234 ffff888077ea82b8 00000002ffffffff ffff88805d440000 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 5882, tgid 5881 (syz.2.2), ts 70296560425, free_ts 70295309542 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_cont_expand_simple+0x13a/0x200 fs/buffer.c:2482 reiserfs_setattr+0x58f/0x11a0 fs/reiserfs/inode.c:3302 notify_change+0xb0d/0xe10 fs/attr.c:499 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 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline] tlb_flush_mmu_free mm/mmu_gather.c:293 [inline] tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392 unmap_region+0x2ed/0x340 mm/mmap.c:2345 do_vmi_align_munmap+0xffe/0x1660 mm/mmap.c:2588 do_vmi_munmap+0x252/0x2d0 mm/mmap.c:2656 __vm_munmap+0x193/0x3c0 mm/mmap.c:2957 __do_sys_munmap mm/mmap.c:2974 [inline] __se_sys_munmap mm/mmap.c:2971 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:2971 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 Memory state around the buggy address: ffff88805b8def00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88805b8def80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88805b8df000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffff88805b8df080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88805b8df100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================