================================================================== BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x92/0x190 lib/list_debug.c:62 Read of size 8 at addr ffff888068af47b8 by task syz.3.1931/11253 CPU: 0 UID: 0 PID: 11253 Comm: syz.3.1931 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 __list_del_entry_valid_or_report+0x92/0x190 lib/list_debug.c:62 __list_del_entry_valid include/linux/list.h:132 [inline] __list_del_entry include/linux/list.h:223 [inline] list_del_init include/linux/list.h:295 [inline] trace_transfers fs/pnode.c:132 [inline] bulk_make_private+0xd9/0x8b0 fs/pnode.c:168 umount_tree+0x582/0xd90 fs/namespace.c:1786 put_mnt_ns+0x1d6/0x2f0 fs/namespace.c:6230 nsproxy_free kernel/nsproxy.c:65 [inline] deactivate_nsproxy+0x41/0x140 kernel/nsproxy.c:79 do_exit+0x696/0x2310 kernel/exit.c:970 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop kernel/entry/common.c:98 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x176/0x620 kernel/entry/common.c:219 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f08f5f9aec1 Code: Unable to access opcode bytes at 0x7f08f5f9ae97. RSP: 002b:fffffffffffffc70 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f08f6215fa0 RCX: 00007f08f5f9aeb9 RDX: 0000000000000000 RSI: fffffffffffffc70 RDI: 0000000001022000 RBP: 00007f08f6008c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f08f6216038 R14: 00007f08f6215fa0 R15: 00007ffc179d8048 Allocated by task 11274: 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:4456 [inline] slab_alloc_node mm/slub.c:4785 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4792 alloc_vfsmnt+0x23/0x420 fs/namespace.c:287 clone_mnt+0x4b/0x9a0 fs/namespace.c:1246 create_new_namespace fs/namespace.c:3098 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0x507/0x1040 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 11253: 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:2667 [inline] slab_free mm/slub.c:6079 [inline] kmem_cache_free+0x180/0x610 mm/slub.c:6205 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:727 irq_exit_rcu+0x9/0x30 kernel/softirq.c:743 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 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 __call_rcu_common kernel/rcu/tree.c:3131 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3251 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Second to 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 task_work_add+0xb6/0x440 kernel/task_work.c:70 mntput_no_expire_slowpath+0x70c/0xbd0 fs/namespace.c:1379 create_new_namespace fs/namespace.c:3162 [inline] open_new_namespace fs/namespace.c:3168 [inline] vfs_open_tree+0xe17/0x1040 fs/namespace.c:3217 __do_sys_open_tree fs/namespace.c:3227 [inline] __se_sys_open_tree fs/namespace.c:3225 [inline] __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3225 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888068af4700 which belongs to the cache mnt_cache of size 352 The buggy address is located 184 bytes inside of freed 352-byte region [ffff888068af4700, ffff888068af4860) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x68af4 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888035e2ca01 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801c2faa00 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800120012 00000000f5000000 ffff888035e2ca01 head: 00fff00000000040 ffff88801c2faa00 dead000000000100 dead000000000122 head: 0000000000000000 0000000800120012 00000000f5000000 ffff888035e2ca01 head: 00fff00000000001 ffffea0001a2bd01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5819, tgid 5819 (syz-executor), ts 86131624750, free_ts 84506248470 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1883 prep_new_page mm/page_alloc.c:1891 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5244 alloc_slab_page mm/slub.c:3235 [inline] allocate_slab+0x7b/0x660 mm/slub.c:3408 new_slab mm/slub.c:3466 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7084 refill_sheaf mm/slub.c:2784 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4533 alloc_from_pcs mm/slub.c:4636 [inline] slab_alloc_node mm/slub.c:4770 [inline] kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4792 alloc_vfsmnt+0x23/0x420 fs/namespace.c:287 clone_mnt+0x4b/0x9a0 fs/namespace.c:1246 copy_tree+0x3d4/0x930 fs/namespace.c:2194 copy_mnt_ns+0x24d/0x990 fs/namespace.c:4246 create_new_namespaces+0xcf/0x6a0 kernel/nsproxy.c:98 unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:226 ksys_unshare+0x4f4/0x900 kernel/fork.c:3173 __do_sys_unshare kernel/fork.c:3244 [inline] __se_sys_unshare kernel/fork.c:3242 [inline] __x64_sys_unshare+0x38/0x50 kernel/fork.c:3242 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 page last free pid 5809 tgid 5809 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1432 [inline] free_unref_folios+0xdd7/0x1520 mm/page_alloc.c:3034 folios_put_refs+0x789/0x8d0 mm/swap.c:1002 free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423 __tlb_batch_free_encoded_pages mm/mmu_gather.c:137 [inline] tlb_batch_pages_flush mm/mmu_gather.c:150 [inline] tlb_flush_mmu_free mm/mmu_gather.c:397 [inline] tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:404 tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:529 unmap_region+0x2a5/0x330 mm/vma.c:488 vms_clear_ptes mm/vma.c:1284 [inline] vms_complete_munmap_vmas+0x493/0xc60 mm/vma.c:1326 do_vmi_align_munmap+0x3b7/0x4b0 mm/vma.c:1585 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1633 __vm_munmap+0x22c/0x3d0 mm/vma.c:3254 __do_sys_munmap mm/mmap.c:1078 [inline] __se_sys_munmap mm/mmap.c:1075 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1075 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888068af4680: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ffff888068af4700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888068af4780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888068af4800: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff888068af4880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ==================================================================