==================================================================
BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x105/0x130 lib/list_debug.c:29
Read of size 8 at addr ffff888075aeaec0 by task syz.0.10006/2925

CPU: 1 UID: 0 PID: 2925 Comm: syz.0.10006 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:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
 __list_add_valid_or_report+0x105/0x130 lib/list_debug.c:29
 __list_add_valid include/linux/list.h:96 [inline]
 __list_add include/linux/list.h:158 [inline]
 list_add include/linux/list.h:177 [inline]
 clone_mnt+0x633/0x930 fs/namespace.c:1275
 copy_tree+0xfc/0xbf0 fs/namespace.c:2159
 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246
 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x455/0xab0 kernel/fork.c:3174
 __do_sys_unshare kernel/fork.c:3245 [inline]
 __se_sys_unshare kernel/fork.c:3243 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa58739c629
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:00007fa588297028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fa587615fa0 RCX: 00007fa58739c629
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000024060400
RBP: 00007fa587432b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa587616038 R14: 00007fa587615fa0 R15: 00007ffd10af6b58
 </TASK>

Allocated by task 2310:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4837
 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287
 clone_mnt+0x4b/0x930 fs/namespace.c:1246
 copy_tree+0x329/0xbf0 fs/namespace.c:2194
 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246
 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x455/0xab0 kernel/fork.c:3174
 __do_sys_unshare kernel/fork.c:3245 [inline]
 __se_sys_unshare kernel/fork.c:3243 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 23:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kmem_cache_free+0x124/0x6a0 mm/slub.c:6254
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869
 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
 run_ksoftirqd kernel/softirq.c:1063 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055
 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 __call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3131
 task_work_run+0x150/0x240 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+0x100/0x4a0 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 include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x67c/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+0x30/0x50 mm/kasan/common.c:57
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 task_work_add+0x28b/0x3b0 kernel/task_work.c:70
 mntput_no_expire_slowpath+0x3da/0xb00 fs/namespace.c:1379
 mntput_no_expire+0x1fd/0x220 fs/namespace.c:1406
 mntput fs/namespace.c:1416 [inline]
 namespace_unlock+0x675/0x920 fs/namespace.c:1713
 do_umount fs/namespace.c:1952 [inline]
 path_umount+0x54e/0x1260 fs/namespace.c:2032
 ksys_umount fs/namespace.c:2055 [inline]
 __do_sys_umount fs/namespace.c:2060 [inline]
 __se_sys_umount fs/namespace.c:2058 [inline]
 __x64_sys_umount+0x16a/0x1a0 fs/namespace.c:2058
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888075aeae00
 which belongs to the cache mnt_cache of size 352
The buggy address is located 192 bytes inside of
 freed 352-byte region [ffff888075aeae00, ffff888075aeaf60)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75aea
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888076abf501
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801ca8ca00 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800120012 00000000f5000000 ffff888076abf501
head: 00fff00000000040 ffff88801ca8ca00 dead000000000100 dead000000000122
head: 0000000000000000 0000000800120012 00000000f5000000 ffff888076abf501
head: 00fff00000000001 ffffea0001d6ba81 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 5833, tgid 5833 (syz-executor), ts 89792759683, free_ts 24875714673
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab mm/slub.c:3444 [inline]
 new_slab+0xa6/0x6d0 mm/slub.c:3502
 refill_objects+0x26b/0x400 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 alloc_full_sheaf mm/slub.c:2825 [inline]
 __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4588
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 kmem_cache_alloc_noprof+0x480/0x6e0 mm/slub.c:4837
 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287
 clone_mnt+0x4b/0x930 fs/namespace.c:1246
 copy_tree+0x329/0xbf0 fs/namespace.c:2194
 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246
 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x455/0xab0 kernel/fork.c:3174
 __do_sys_unshare kernel/fork.c:3245 [inline]
 __se_sys_unshare kernel/fork.c:3243 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
 __free_pages mm/page_alloc.c:5369 [inline]
 free_contig_range+0xde/0x1d0 mm/page_alloc.c:7373
 debug_vm_pgtable_free_huge_page mm/debug_vm_pgtable.c:980 [inline]
 destroy_args+0xa8/0x7a0 mm/debug_vm_pgtable.c:993
 debug_vm_pgtable+0x1b66/0x34c0 mm/debug_vm_pgtable.c:1368
 do_one_initcall+0x11d/0x760 init/main.c:1382
 do_initcall_level init/main.c:1444 [inline]
 do_initcalls init/main.c:1460 [inline]
 do_basic_setup init/main.c:1479 [inline]
 kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692
 kernel_init+0x1f/0x1e0 init/main.c:1582
 ret_from_fork+0x754/0xd80 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:
 ffff888075aead80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888075aeae00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888075aeae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888075aeaf00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888075aeaf80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
==================================================================
 slab mnt_cache start ffff888075aeae00 pointer offset 184 size 352
==================================================================
BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x11f/0x130 lib/list_debug.c:29
Read of size 8 at addr ffff888075aeaec0 by task syz.0.10006/2925

CPU: 0 UID: 0 PID: 2925 Comm: syz.0.10006 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
 __list_add_valid_or_report+0x11f/0x130 lib/list_debug.c:29
 __list_add_valid include/linux/list.h:96 [inline]
 __list_add include/linux/list.h:158 [inline]
 list_add include/linux/list.h:177 [inline]
 clone_mnt+0x633/0x930 fs/namespace.c:1275
 copy_tree+0xfc/0xbf0 fs/namespace.c:2159
 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246
 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x455/0xab0 kernel/fork.c:3174
 __do_sys_unshare kernel/fork.c:3245 [inline]
 __se_sys_unshare kernel/fork.c:3243 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa58739c629
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:00007fa588297028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fa587615fa0 RCX: 00007fa58739c629
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000024060400
RBP: 00007fa587432b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa587616038 R14: 00007fa587615fa0 R15: 00007ffd10af6b58
 </TASK>

Allocated by task 2310:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4837
 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287
 clone_mnt+0x4b/0x930 fs/namespace.c:1246
 copy_tree+0x329/0xbf0 fs/namespace.c:2194
 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246
 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x455/0xab0 kernel/fork.c:3174
 __do_sys_unshare kernel/fork.c:3245 [inline]
 __se_sys_unshare kernel/fork.c:3243 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 23:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kmem_cache_free+0x124/0x6a0 mm/slub.c:6254
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869
 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
 run_ksoftirqd kernel/softirq.c:1063 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055
 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 __call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3131
 task_work_run+0x150/0x240 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+0x100/0x4a0 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 include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x67c/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+0x30/0x50 mm/kasan/common.c:57
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 task_work_add+0x28b/0x3b0 kernel/task_work.c:70
 mntput_no_expire_slowpath+0x3da/0xb00 fs/namespace.c:1379
 mntput_no_expire+0x1fd/0x220 fs/namespace.c:1406
 mntput fs/namespace.c:1416 [inline]
 namespace_unlock+0x675/0x920 fs/namespace.c:1713
 do_umount fs/namespace.c:1952 [inline]
 path_umount+0x54e/0x1260 fs/namespace.c:2032
 ksys_umount fs/namespace.c:2055 [inline]
 __do_sys_umount fs/namespace.c:2060 [inline]
 __se_sys_umount fs/namespace.c:2058 [inline]
 __x64_sys_umount+0x16a/0x1a0 fs/namespace.c:2058
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888075aeae00
 which belongs to the cache mnt_cache of size 352
The buggy address is located 192 bytes inside of
 freed 352-byte region [ffff888075aeae00, ffff888075aeaf60)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75aea
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888076abf501
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801ca8ca00 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800120012 00000000f5000000 ffff888076abf501
head: 00fff00000000040 ffff88801ca8ca00 dead000000000100 dead000000000122
head: 0000000000000000 0000000800120012 00000000f5000000 ffff888076abf501
head: 00fff00000000001 ffffea0001d6ba81 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 5833, tgid 5833 (syz-executor), ts 89792759683, free_ts 24875714673
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab mm/slub.c:3444 [inline]
 new_slab+0xa6/0x6d0 mm/slub.c:3502
 refill_objects+0x26b/0x400 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 alloc_full_sheaf mm/slub.c:2825 [inline]
 __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4588
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 kmem_cache_alloc_noprof+0x480/0x6e0 mm/slub.c:4837
 alloc_vfsmnt+0x23/0x6a0 fs/namespace.c:287
 clone_mnt+0x4b/0x930 fs/namespace.c:1246
 copy_tree+0x329/0xbf0 fs/namespace.c:2194
 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246
 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x455/0xab0 kernel/fork.c:3174
 __do_sys_unshare kernel/fork.c:3245 [inline]
 __se_sys_unshare kernel/fork.c:3243 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
 __free_pages mm/page_alloc.c:5369 [inline]
 free_contig_range+0xde/0x1d0 mm/page_alloc.c:7373
 debug_vm_pgtable_free_huge_page mm/debug_vm_pgtable.c:980 [inline]
 destroy_args+0xa8/0x7a0 mm/debug_vm_pgtable.c:993
 debug_vm_pgtable+0x1b66/0x34c0 mm/debug_vm_pgtable.c:1368
 do_one_initcall+0x11d/0x760 init/main.c:1382
 do_initcall_level init/main.c:1444 [inline]
 do_initcalls init/main.c:1460 [inline]
 do_basic_setup init/main.c:1479 [inline]
 kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692
 kernel_init+0x1f/0x1e0 init/main.c:1582
 ret_from_fork+0x754/0xd80 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:
 ffff888075aead80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888075aeae00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888075aeae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888075aeaf00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888075aeaf80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
==================================================================
list_add corruption. next->prev should be prev (ffff888075ae25f8), but was ffff888075aeaeb8. (next=ffff888075aeaeb8).
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:29!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 2925 Comm: syz.0.10006 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__list_add_valid_or_report+0xc3/0x130 lib/list_debug.c:29
Code: b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 6b 48 8b 53 08 48 89 d9 4c 89 ee 48 c7 c7 60 f0 1a 8c e8 ce 27 26 fc 90 <0f> 0b 4c 89 ef e8 b3 b2 52 fd 4c 89 ea 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc90003377c30 EFLAGS: 00010282
RAX: 0000000000000075 RBX: ffff888075aeaeb8 RCX: 0000000000000000
RDX: 0000000000000075 RSI: ffffffff81e76a69 RDI: fffff5200066ef77
RBP: ffff8880724fa7b8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 6464615f7473696c R12: ffff888075aeaec0
R13: ffff888075ae25f8 R14: ffff888075ae25f8 R15: ffff8880724fa7b8
FS:  00007fa5882976c0(0000) GS:ffff88812444a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd51496d000 CR3: 0000000040745000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 __list_add_valid include/linux/list.h:96 [inline]
 __list_add include/linux/list.h:158 [inline]
 list_add include/linux/list.h:177 [inline]
 clone_mnt+0x633/0x930 fs/namespace.c:1275
 copy_tree+0xfc/0xbf0 fs/namespace.c:2159
 copy_mnt_ns+0x2bd/0xc30 fs/namespace.c:4246
 create_new_namespaces+0xd3/0xac0 kernel/nsproxy.c:98
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x455/0xab0 kernel/fork.c:3174
 __do_sys_unshare kernel/fork.c:3245 [inline]
 __se_sys_unshare kernel/fork.c:3243 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3243
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa58739c629
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:00007fa588297028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fa587615fa0 RCX: 00007fa58739c629
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000024060400
RBP: 00007fa587432b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa587616038 R14: 00007fa587615fa0 R15: 00007ffd10af6b58
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_add_valid_or_report+0xc3/0x130 lib/list_debug.c:29
Code: b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 6b 48 8b 53 08 48 89 d9 4c 89 ee 48 c7 c7 60 f0 1a 8c e8 ce 27 26 fc 90 <0f> 0b 4c 89 ef e8 b3 b2 52 fd 4c 89 ea 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc90003377c30 EFLAGS: 00010282
RAX: 0000000000000075 RBX: ffff888075aeaeb8 RCX: 0000000000000000
RDX: 0000000000000075 RSI: ffffffff81e76a69 RDI: fffff5200066ef77
RBP: ffff8880724fa7b8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 6464615f7473696c R12: ffff888075aeaec0
R13: ffff888075ae25f8 R14: ffff888075ae25f8 R15: ffff8880724fa7b8
FS:  00007fa5882976c0(0000) GS:ffff88812444a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6c2e815286 CR3: 0000000040745000 CR4: 0000000000350ef0