==================================================================
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 ffff88807627d058 by task syz.2.158/7059

CPU: 0 UID: 0 PID: 7059 Comm: syz.2.158 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:
 <TASK>
 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: 0033:0x7ff64498ebe9
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:00007ff6457cd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000019
RAX: ffffffffffffffda RBX: 00007ff644bb6270 RCX: 00007ff64498ebe9
RDX: 0000000000001000 RSI: 0000000000001000 RDI: 0000200000ffc000
RBP: 00007ff644a11e19 R08: 0000200000fff000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff644bb6308 R14: 00007ff644bb6270 R15: 00007ffd2cd43978
 </TASK>

Allocated by task 7059:
 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_alloc+0x24/0x140 mm/vma_init.c:31
 __mmap_new_vma mm/vma.c:2461 [inline]
 __mmap_region mm/vma.c:2669 [inline]
 mmap_region+0xdc7/0x20c0 mm/vma.c:2739
 do_mmap+0xc45/0x10d0 mm/mmap.c:558
 do_shmat+0x96a/0xca0 ipc/shm.c:1660
 __do_sys_shmat ipc/shm.c:1696 [inline]
 __se_sys_shmat ipc/shm.c:1691 [inline]
 __x64_sys_shmat+0x9c/0xf0 ipc/shm.c:1691
 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 5868:
 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
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

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 ffff88807627d000
 which belongs to the cache vm_area_struct of size 256
The buggy address is located 88 bytes inside of
 freed 256-byte region [ffff88807627d000, ffff88807627d100)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7627d
memcg:ffff888074ef8181
ksm flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88814047eb40 ffffea0001d847c0 0000000000000003
raw: 0000000000000000 00000000000c000c 00000000f5000000 ffff888074ef8181
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 6684, tgid 6684 (dhcpcd-run-hook), ts 107104798742, free_ts 104372001515
 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 10 tgid 10 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
 vfree+0x25a/0x400 mm/vmalloc.c:3434
 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3353
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 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:
 ffff88807627cf00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88807627cf80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88807627d000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88807627d080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807627d100: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
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