================================================================== BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x617/0xaa0 fs/reiserfs/lbalance.c:-1 Read of size 48 at addr ffff888050a3fff0 by task syz.3.202/5563 CPU: 1 PID: 5563 Comm: syz.3.202 Not tainted 6.1.148-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 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+0x617/0xaa0 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 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+0xc2fa/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+0x376/0x7c0 fs/reiserfs/inode.c:2310 reiserfs_setattr+0xcae/0x1240 fs/reiserfs/inode.c:3395 notify_change+0xc74/0xf40 fs/attr.c:499 do_truncate+0x197/0x220 fs/open.c:65 vfs_truncate+0x262/0x2f0 fs/open.c:111 do_sys_truncate+0xdc/0x190 fs/open.c:134 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f20cbb8ebe9 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:00007f20cc92b038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c RAX: ffffffffffffffda RBX: 00007f20cbdb6180 RCX: 00007f20cbb8ebe9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00002000000000c0 RBP: 00007f20cbc11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f20cbdb6218 R14: 00007f20cbdb6180 R15: 00007ffe464f5768 The buggy address belongs to the physical page: page:ffffea0001428fc0 refcount:2 mapcount:0 mapping:ffff88801793a8f8 index:0x246 pfn:0x50a3f memcg:ffff888074b00000 aops:def_blk_aops ino:700003 flags: 0xfff58000002052(referenced|lru|workingset|private|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff58000002052 ffffea00014531c8 ffffea0001453008 ffff88801793a8f8 raw: 0000000000000246 ffff888053fdb9f8 00000002ffffffff ffff888074b00000 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 5515, tgid 5513 (syz.3.202), ts 137097674061, free_ts 137071670523 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532 prep_new_page mm/page_alloc.c:2539 [inline] get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614 folio_alloc+0x1c/0x60 mm/mempolicy.c:2292 filemap_alloc_folio+0xdb/0x460 mm/filemap.c:999 __filemap_get_folio+0x697/0xdd0 mm/filemap.c:1993 pagecache_get_page+0x26/0x250 mm/folio-compat.c:110 find_or_create_page include/linux/pagemap.h:646 [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+0x2d8/0xb20 fs/buffer.c:1333 sb_getblk include/linux/buffer_head.h:356 [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+0x1bdc/0x3ef0 fs/reiserfs/inode.c:1069 __block_write_begin_int+0x54b/0x1a70 fs/buffer.c:1991 reiserfs_write_begin+0x206/0x4c0 fs/reiserfs/inode.c:2775 generic_cont_expand_simple+0x136/0x1f0 fs/buffer.c:2347 reiserfs_setattr+0x639/0x1240 fs/reiserfs/inode.c:3305 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+0x8b4/0x9a0 mm/page_alloc.c:3384 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525 release_pages+0x1f92/0x2200 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+0xff/0x210 mm/mmu_gather.c:261 tlb_finish_mmu+0xbd/0x1c0 mm/mmu_gather.c:361 unmap_region+0x272/0x2c0 mm/mmap.c:2339 do_mas_align_munmap+0xc57/0x1220 mm/mmap.c:2588 do_mas_munmap+0x240/0x2b0 mm/mmap.c:2646 __vm_munmap+0x18d/0x290 mm/mmap.c:2932 __do_sys_munmap mm/mmap.c:2957 [inline] __se_sys_munmap mm/mmap.c:2954 [inline] __x64_sys_munmap+0x5c/0x70 mm/mmap.c:2954 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Memory state around the buggy address: ffff888050a3ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888050a3ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888050a40000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888050a40080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888050a40100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================