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BUG: KASAN: use-after-free in read_pnet include/net/net_namespace.h:419 [inline]
BUG: KASAN: use-after-free in dev_net include/linux/netdevice.h:2741 [inline]
BUG: KASAN: use-after-free in nf_hook_entry_head+0x1f1/0x2c0 net/netfilter/core.c:319
Read of size 8 at addr ffff888072f70108 by task kworker/u8:5/22126

CPU: 1 UID: 0 PID: 22126 Comm: kworker/u8:5 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 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
 read_pnet include/net/net_namespace.h:419 [inline]
 dev_net include/linux/netdevice.h:2741 [inline]
 nf_hook_entry_head+0x1f1/0x2c0 net/netfilter/core.c:319
 __nf_unregister_net_hook+0x74/0x6f0 net/netfilter/core.c:491
 nft_unregister_flowtable_ops net/netfilter/nf_tables_api.c:8895 [inline]
 __nft_unregister_flowtable_net_hooks net/netfilter/nf_tables_api.c:8910 [inline]
 __nft_release_hook net/netfilter/nf_tables_api.c:11899 [inline]
 __nft_release_hooks net/netfilter/nf_tables_api.c:11913 [inline]
 nf_tables_pre_exit_net+0x64a/0x900 net/netfilter/nf_tables_api.c:12064
 ops_pre_exit_list net/core/net_namespace.c:161 [inline]
 ops_undo_list+0x187/0x940 net/core/net_namespace.c:234
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:704
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888072f73c00 pfn:0x72f70
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 00fff00000000000 ffffea0000d63408 ffffea00012c0b08 0000000000000000
raw: ffff888072f73c00 0000000000000002 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 30999, tgid 30998 (syz.8.6162), ts 1782851072285, free_ts 1796210345084
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3269 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3458
 new_slab mm/slub.c:3516 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7153
 refill_sheaf mm/slub.c:2818 [inline]
 __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4592
 alloc_from_pcs mm/slub.c:4695 [inline]
 slab_alloc_node mm/slub.c:4829 [inline]
 __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5353
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 genradix_alloc_node include/linux/generic-radix-tree.h:101 [inline]
 __genradix_ptr_alloc+0x352/0x4a0 lib/generic-radix-tree.c:69
 __genradix_prealloc+0x44/0x90 lib/generic-radix-tree.c:216
 sctp_stream_alloc_out net/sctp/stream.c:104 [inline]
 sctp_stream_init+0x5f0/0x940 net/sctp/stream.c:149
 sctp_association_init net/sctp/associola.c:232 [inline]
 sctp_association_new+0x10dd/0x25e0 net/sctp/associola.c:296
 sctp_connect_new_asoc+0x2e4/0x6b0 net/sctp/socket.c:1092
 sctp_sendmsg_new_asoc net/sctp/socket.c:1692 [inline]
 sctp_sendmsg+0x1528/0x2c10 net/sctp/socket.c:2003
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 __sys_sendto+0x627/0x7a0 net/socket.c:2206
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2209
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 30316 tgid 30316 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __slab_free+0x263/0x2b0 mm/slub.c:5551
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4515 [inline]
 slab_alloc_node mm/slub.c:4844 [inline]
 kmem_cache_alloc_lru_noprof+0x2b8/0x640 mm/slub.c:4863
 shmem_alloc_inode+0x28/0x40 mm/shmem.c:5167
 alloc_inode+0x6a/0x1b0 fs/inode.c:347
 new_inode+0x22/0x170 fs/inode.c:1185
 __shmem_get_inode mm/shmem.c:3079 [inline]
 shmem_get_inode+0x347/0xe60 mm/shmem.c:3154
 shmem_mknod+0x191/0x360 mm/shmem.c:3884
 shmem_mkdir+0x33/0x70 mm/shmem.c:3947
 vfs_mkdir+0x413/0x630 fs/namei.c:5233
 filename_mkdirat+0x285/0x510 fs/namei.c:5266
 __do_sys_mkdirat fs/namei.c:5287 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5284
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff888072f70000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888072f70080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888072f70100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff888072f70180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888072f70200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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