================================================================== BUG: KASAN: slab-use-after-free in madvise_walk_vmas+0x661/0xae0 mm/madvise.c:1726 Read of size 8 at addr ffff88803322aa08 by task syz.0.3603/14995 CPU: 1 UID: 0 PID: 14995 Comm: syz.0.3603 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 madvise_walk_vmas+0x661/0xae0 mm/madvise.c:1726 madvise_do_behavior+0x386/0x540 mm/madvise.c:1929 do_madvise+0x1fa/0x2e0 mm/madvise.c:2022 __do_sys_madvise mm/madvise.c:2031 [inline] __se_sys_madvise mm/madvise.c:2029 [inline] __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2029 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6f8599c799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6f8681a028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f6f85c16090 RCX: 00007f6f8599c799 RDX: 0000000000000019 RSI: 0000000008000000 RDI: 0000200000000000 RBP: 00007f6f85a32c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6f85c16128 R14: 00007f6f85c16090 R15: 00007ffd2a0e3548 Allocated by task 5846: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 dup_mmap+0x8b1/0x1d90 mm/mmap.c:1786 dup_mm kernel/fork.c:1533 [inline] copy_mm+0x13b/0x4a0 kernel/fork.c:1585 copy_process+0x1efd/0x4430 kernel/fork.c:2260 kernel_clone+0x26d/0x8e0 kernel/fork.c:2709 __do_sys_clone kernel/fork.c:2850 [inline] __se_sys_clone kernel/fork.c:2834 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2834 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15002: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free_after_rcu_debug+0x12a/0x220 mm/slub.c:6304 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 lock_sock include/net/sock.h:1713 [inline] packet_do_bind+0x33/0xe10 net/packet/af_packet.c:3198 __sys_bind_socket net/socket.c:1932 [inline] __sys_bind+0x2e3/0x410 net/socket.c:1963 __do_sys_bind net/socket.c:1968 [inline] __se_sys_bind net/socket.c:1966 [inline] __x64_sys_bind+0x7a/0x90 net/socket.c:1966 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2650 [inline] slab_free mm/slub.c:6242 [inline] kmem_cache_free+0x44f/0x650 mm/slub.c:6369 remove_vma mm/vma.c:473 [inline] vms_complete_munmap_vmas+0x929/0xc60 mm/vma.c:1361 do_vmi_align_munmap+0x3b7/0x4b0 mm/vma.c:1604 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1652 do_munmap+0xf9/0x170 mm/mmap.c:1067 mremap_to+0x353/0x880 mm/mremap.c:1448 do_mremap mm/mremap.c:1999 [inline] __do_sys_mremap mm/mremap.c:2055 [inline] __se_sys_mremap+0xe6d/0x11d0 mm/mremap.c:2023 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803322aa00 which belongs to the cache vm_area_struct of size 256 The buggy address is located 8 bytes inside of freed 256-byte region [ffff88803322aa00, ffff88803322ab00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803322adc0 pfn:0x3322a memcg:ffff88803322af01 flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000200 ffff88801c294b40 ffffea0001163f90 ffffea0001dba810 raw: ffff88803322adc0 00000008000c000b 00000000f5000000 ffff88803322af01 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11045, tgid 11045 (syz.0.2085), ts 233915893282, free_ts 233883108694 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3938 __alloc_frozen_pages_noprof+0x233/0x3d0 mm/page_alloc.c:5218 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab+0x77/0x660 mm/slub.c:3467 new_slab mm/slub.c:3525 [inline] refill_objects+0x339/0x3d0 mm/slub.c:7247 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4905 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 __split_vma+0x1dc/0xa40 mm/vma.c:516 split_vma mm/vma.c:599 [inline] vma_modify+0x88a/0x1e10 mm/vma.c:1691 vma_modify_flags+0x24b/0x330 mm/vma.c:1719 mprotect_fixup+0x62a/0xb60 mm/mprotect.c:759 do_mprotect_pkey+0x8d5/0xd20 mm/mprotect.c:937 __do_sys_mprotect mm/mprotect.c:958 [inline] __se_sys_mprotect mm/mprotect.c:955 [inline] __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:955 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 23 tgid 23 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2935 __tlb_remove_table_free mm/mmu_gather.c:228 [inline] tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88803322a900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88803322a980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff88803322aa00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803322aa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803322ab00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ==================================================================