================================================================== BUG: KASAN: use-after-free in leaf_paste_in_buffer+0x1c8/0xab0 fs/reiserfs/lbalance.c:1017 Write of size 3936 at addr ffff88804dc64140 by task syz.8.671/7285 CPU: 1 PID: 7285 Comm: syz.8.671 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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 memmove+0x3c/0x60 mm/kasan/shadow.c:55 leaf_paste_in_buffer+0x1c8/0xab0 fs/reiserfs/lbalance.c:1017 leaf_copy_boundary_item+0xc75/0x2190 fs/reiserfs/lbalance.c:199 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_paste_left_shift fs/reiserfs/do_balan.c:458 [inline] balance_leaf_paste_left fs/reiserfs/do_balan.c:592 [inline] balance_leaf_left fs/reiserfs/do_balan.c:613 [inline] balance_leaf+0x2c05/0x10e60 fs/reiserfs/do_balan.c:1409 do_balance+0x2fa/0x930 fs/reiserfs/do_balan.c:1888 reiserfs_paste_into_item+0x69b/0x7e0 fs/reiserfs/stree.c:2159 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_perform_write+0x2aa/0x530 mm/filemap.c:3785 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x712/0xd00 fs/read_write.c:594 ksys_write+0x14d/0x250 fs/read_write.c:647 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: 0033:0x7f0339127749 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:00007f033738e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f033937dfa0 RCX: 00007f0339127749 RDX: 00000000000000f8 RSI: 00002000000003c0 RDI: 0000000000000006 RBP: 00007f03391abf91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f033937e038 R14: 00007f033937dfa0 R15: 00007ffe7599ba68 The buggy address belongs to the page: page:ffffea0001371900 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x4dc64 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 ffffea0001c91088 ffffea0001221a88 0000000000000000 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 0, migratetype Movable, gfp_mask 0x1100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 7299, ts 299486271541, free_ts 300241585823 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 alloc_pages_vma+0x393/0x7c0 mm/mempolicy.c:2146 do_anonymous_page mm/memory.c:3838 [inline] handle_pte_fault mm/memory.c:4648 [inline] __handle_mm_fault mm/memory.c:4785 [inline] handle_mm_fault+0x237f/0x43b0 mm/memory.c:4883 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 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+0xc5/0x170 mm/mmu_gather.c:247 zap_pte_range mm/memory.c:1456 [inline] zap_pmd_range mm/memory.c:1505 [inline] zap_pud_range mm/memory.c:1534 [inline] zap_p4d_range mm/memory.c:1555 [inline] unmap_page_range+0x2096/0x2520 mm/memory.c:1576 unmap_vmas+0x11b/0x230 mm/memory.c:1653 exit_mmap+0x38f/0x5f0 mm/mmap.c:3216 __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 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 Memory state around the buggy address: ffff88804dc64000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88804dc64080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88804dc64100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88804dc64180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88804dc64200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================