================================================================== BUG: KASAN: slab-use-after-free in vma_multi_allowed mm/mremap.c:1623 [inline] BUG: KASAN: slab-use-after-free in remap_move mm/mremap.c:1884 [inline] BUG: KASAN: slab-use-after-free in do_mremap mm/mremap.c:1923 [inline] BUG: KASAN: slab-use-after-free in __do_sys_mremap mm/mremap.c:1987 [inline] BUG: KASAN: slab-use-after-free in __se_sys_mremap+0xb33/0x1150 mm/mremap.c:1955 Read of size 8 at addr ffff888038ecce18 by task syz.2.1540/15240 CPU: 1 UID: 0 PID: 15240 Comm: syz.2.1540 Not tainted 6.17.0-rc2-next-20250818-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 vma_multi_allowed mm/mremap.c:1623 [inline] remap_move mm/mremap.c:1884 [inline] do_mremap mm/mremap.c:1923 [inline] __do_sys_mremap mm/mremap.c:1987 [inline] __se_sys_mremap+0xb33/0x1150 mm/mremap.c:1955 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd3dd98ebe9 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:00007fd3de7af038 EFLAGS: 00000246 ORIG_RAX: 0000000000000019 RAX: ffffffffffffffda RBX: 00007fd3ddbb5fa0 RCX: 00007fd3dd98ebe9 RDX: 0000000000003000 RSI: 0000000000003000 RDI: 0000200000001000 RBP: 00007fd3dda11e19 R08: 0000200000ffd000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd3ddbb6038 R14: 00007fd3ddbb5fa0 R15: 00007ffdbf57c428 Allocated by task 5866: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4236 vm_area_dup+0x2b/0x680 mm/vma_init.c:122 dup_mmap+0x90c/0x1ac0 mm/mmap.c:1780 dup_mm kernel/fork.c:1488 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1540 copy_process+0x1706/0x3c00 kernel/fork.c:2178 kernel_clone+0x21e/0x840 kernel/fork.c:2608 __do_sys_clone kernel/fork.c:2751 [inline] __se_sys_clone kernel/fork.c:2735 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2735 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 23: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free_after_rcu_debug+0x129/0x2a0 mm/slub.c:4730 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x283/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 slab_free_hook mm/slub.c:2378 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x2f6/0x400 mm/slub.c:4782 remove_vma mm/vma.c:468 [inline] vms_complete_munmap_vmas+0x626/0x8a0 mm/vma.c:1293 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1536 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584 do_munmap+0xe1/0x140 mm/mmap.c:1068 mremap_to+0x2df/0x7a0 mm/mremap.c:1372 remap_move mm/mremap.c:1879 [inline] do_mremap mm/mremap.c:1923 [inline] __do_sys_mremap mm/mremap.c:1987 [inline] __se_sys_mremap+0xadf/0x1150 mm/mremap.c:1955 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888038eccdc0 which belongs to the cache vm_area_struct of size 256 The buggy address is located 88 bytes inside of freed 256-byte region [ffff888038eccdc0, ffff888038eccec0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x38ecc memcg:ffff888023de8681 anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801bed5b40 0000000000000000 dead000000000001 raw: 0000000000000000 00000000000c000c 00000000f5000000 ffff888023de8681 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 13493, tgid 13493 (dhcpcd-run-hook), ts 543693663160, free_ts 543674086054 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab+0x8a/0x370 mm/slub.c:2655 new_slab mm/slub.c:2709 [inline] ___slab_alloc+0xbeb/0x1410 mm/slub.c:3891 __slab_alloc mm/slub.c:3981 [inline] __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] kmem_cache_alloc_noprof+0x283/0x3c0 mm/slub.c:4236 vm_area_dup+0x2b/0x680 mm/vma_init.c:122 dup_mmap+0x90c/0x1ac0 mm/mmap.c:1780 dup_mm kernel/fork.c:1488 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1540 copy_process+0x1706/0x3c00 kernel/fork.c:2178 kernel_clone+0x21e/0x840 kernel/fork.c:2608 __do_sys_clone kernel/fork.c:2751 [inline] __se_sys_clone kernel/fork.c:2735 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2735 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 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:1395 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895 pagetable_free include/linux/mm.h:2949 [inline] pagetable_dtor_free include/linux/mm.h:3047 [inline] __tlb_remove_table+0x2d2/0x3b0 include/asm-generic/tlb.h:220 __tlb_remove_table_free mm/mmu_gather.c:227 [inline] tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:290 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x283/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888038eccd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888038eccd80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff888038ecce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888038ecce80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888038eccf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================