================================================================== BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x615/0xab0 fs/reiserfs/lbalance.c:-1 Read of size 48 at addr ffff888054930ff0 by task syz.5.185/5340 CPU: 0 PID: 5340 Comm: syz.5.185 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x27b/0x290 mm/kasan/generic.c:189 memcpy+0x25/0x60 mm/kasan/shadow.c:65 leaf_paste_in_buffer+0x615/0xab0 fs/reiserfs/lbalance.c:-1 leaf_copy_dir_entries+0x56c/0x8f0 fs/reiserfs/lbalance.c:108 leaf_copy_boundary_item+0xb8c/0x2190 fs/reiserfs/lbalance.c:168 leaf_copy_items fs/reiserfs/lbalance.c:551 [inline] leaf_move_items+0x84a/0xde0 fs/reiserfs/lbalance.c:726 leaf_shift_left+0xb9/0x450 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+0x1dbd/0x10e60 fs/reiserfs/do_balan.c:1393 do_balance+0x2fa/0x930 fs/reiserfs/do_balan.c:1888 reiserfs_cut_from_item+0x1391/0x1ef0 fs/reiserfs/stree.c:1838 reiserfs_do_truncate+0xa90/0x13e0 fs/reiserfs/stree.c:1973 reiserfs_truncate_file+0x632/0xdc0 fs/reiserfs/inode.c:2318 reiserfs_setattr+0xaa7/0x1010 fs/reiserfs/inode.c:3409 notify_change+0xbcd/0xee0 fs/attr.c:505 do_truncate+0x197/0x220 fs/open.c:65 handle_truncate fs/namei.c:3273 [inline] do_open fs/namei.c:3620 [inline] path_openat+0x28af/0x2f30 fs/namei.c:3750 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777 do_sys_openat2+0x142/0x4a0 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_creat fs/open.c:1347 [inline] __se_sys_creat fs/open.c:1341 [inline] __x64_sys_creat+0x8c/0xb0 fs/open.c:1341 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f40f3e86749 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:00007f40f20cc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f40f40dd090 RCX: 00007f40f3e86749 RDX: 0000000000000000 RSI: 000000000000008b RDI: 00002000000000c0 RBP: 00007f40f3f0af91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f40f40dd128 R14: 00007f40f40dd090 R15: 00007fff218f2e48 The buggy address belongs to the page: page:ffffea0001524c00 refcount:2 mapcount:0 mapping:ffff888140892030 index:0x214 pfn:0x54930 memcg:ffff888079758000 aops:def_blk_aops ino:700005 flags: 0xfff00000002032(referenced|lru|active|private|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000002032 ffffea00012ae308 ffffea000168a5c8 ffff888140892030 raw: 0000000000000214 ffff888061d662b8 00000002ffffffff ffff888079758000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 5314, ts 512693489068, free_ts 512647287905 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487 __page_cache_alloc+0xd2/0x3f0 mm/filemap.c:1022 pagecache_get_page+0x986/0xef0 mm/filemap.c:1940 find_or_create_page include/linux/pagemap.h:420 [inline] grow_dev_page fs/buffer.c:949 [inline] grow_buffers fs/buffer.c:1014 [inline] __getblk_slow fs/buffer.c:1041 [inline] __getblk_gfp+0x249/0xb70 fs/buffer.c:1336 sb_getblk include/linux/buffer_head.h:361 [inline] get_empty_nodes+0x511/0x8c0 fs/reiserfs/fix_node.c:890 fix_nodes+0x1e69/0x82d0 fs/reiserfs/fix_node.c:2662 reiserfs_paste_into_item+0x5c8/0x7e0 fs/reiserfs/stree.c:2130 reiserfs_get_block+0x1bde/0x4100 fs/reiserfs/inode.c:1077 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012 reiserfs_write_begin+0x34b/0x810 fs/reiserfs/inode.c:2790 generic_cont_expand_simple+0xe9/0x190 fs/buffer.c:2362 reiserfs_setattr+0x42f/0x1010 fs/reiserfs/inode.c:3319 notify_change+0xbcd/0xee0 fs/attr.c:505 do_truncate+0x197/0x220 fs/open.c:65 vfs_truncate+0x262/0x2f0 fs/open.c:111 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page_list+0x122/0x7e0 mm/page_alloc.c:3433 release_pages+0x184b/0x1bb0 mm/swap.c:963 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:240 [inline] tlb_flush_mmu mm/mmu_gather.c:247 [inline] tlb_finish_mmu+0x164/0x2e0 mm/mmu_gather.c:338 exit_mmap+0x3a6/0x5f0 mm/mmap.c:3218 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x5a1/0x20a0 kernel/exit.c:870 do_group_exit+0x12e/0x300 kernel/exit.c:997 __do_sys_exit_group kernel/exit.c:1008 [inline] __se_sys_exit_group kernel/exit.c:1006 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1006 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Memory state around the buggy address: ffff888054930f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888054930f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888054931000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888054931080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888054931100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 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