==================================================================
BUG: KASAN: slab-use-after-free in read_pnet include/net/net_namespace.h:414 [inline]
BUG: KASAN: slab-use-after-free in sock_net include/net/sock.h:700 [inline]
BUG: KASAN: slab-use-after-free in inet_match include/net/inet_hashtables.h:347 [inline]
BUG: KASAN: slab-use-after-free in __inet_lookup_established+0x20d/0x850 net/ipv4/inet_hashtables.c:549
Read of size 8 at addr ffff8880380c4030 by task kworker/1:11/6551

CPU: 1 UID: 0 PID: 6551 Comm: kworker/1:11 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events mptcp_worker
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:414 [inline]
 sock_net include/net/sock.h:700 [inline]
 inet_match include/net/inet_hashtables.h:347 [inline]
 __inet_lookup_established+0x20d/0x850 net/ipv4/inet_hashtables.c:549
 __inet_lookup include/net/inet_hashtables.h:405 [inline]
 __inet_lookup_skb include/net/inet_hashtables.h:490 [inline]
 tcp_v4_rcv+0x104d/0x3780 net/ipv4/tcp_ipv4.c:2196
 ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:207
 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6152 [inline]
 __netif_receive_skb net/core/dev.c:6265 [inline]
 process_backlog+0x569/0xc60 net/core/dev.c:6617
 __napi_poll+0xae/0x530 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0x696/0xe00 net/core/dev.c:7896
 handle_softirqs+0x1de/0x640 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302
 mptcp_pm_send_ack net/mptcp/pm.c:211 [inline]
 mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1
 mptcp_pm_worker+0x174/0x350 net/mptcp/pm.c:1010
 mptcp_worker+0xd2/0x1450 net/mptcp/protocol.c:2931
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 24824:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_noprof+0x235/0x7c0 mm/slub.c:5669
 kmalloc_noprof include/linux/slab.h:961 [inline]
 sk_prot_alloc+0xe7/0x210 net/core/sock.c:2245
 sk_clone+0x7f/0x1000 net/core/sock.c:2481
 sk_clone_lock include/net/sock.h:1836 [inline]
 inet_csk_clone_lock+0x2b/0x5c0 net/ipv4/inet_connection_sock.c:1197
 tcp_create_openreq_child+0x30/0x2b10 net/ipv4/tcp_minisocks.c:548
 tcp_v4_syn_recv_sock+0x167/0xfc0 net/ipv4/tcp_ipv4.c:1726
 tcp_v6_syn_recv_sock+0x153/0x1a80 net/ipv6/tcp_ipv6.c:1337
 subflow_syn_recv_sock+0x286/0x1400 net/mptcp/subflow.c:859
 tcp_check_req+0x115b/0x1bb0 net/ipv4/tcp_minisocks.c:910
 tcp_v4_rcv+0x179b/0x3780 net/ipv4/tcp_ipv4.c:2247
 ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:207
 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6152 [inline]
 __netif_receive_skb net/core/dev.c:6265 [inline]
 process_backlog+0x569/0xc60 net/core/dev.c:6617
 __napi_poll+0xae/0x530 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0x696/0xe00 net/core/dev.c:7896
 handle_softirqs+0x1de/0x640 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline]
 __dev_queue_xmit+0x1eba/0x3990 net/core/dev.c:4859
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 neigh_hh_output include/net/neighbour.h:540 [inline]
 neigh_output include/net/neighbour.h:554 [inline]
 ip_finish_output2+0xba2/0x1060 net/ipv4/ip_output.c:237
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
 ip_local_out net/ipv4/ip_output.c:131 [inline]
 __ip_queue_xmit+0x1198/0x1be0 net/ipv4/ip_output.c:534
 __tcp_transmit_skb+0x253b/0x3ad0 net/ipv4/tcp_output.c:1631
 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6787 [inline]
 tcp_rcv_state_process+0x2e88/0x46c0 net/ipv4/tcp_input.c:6981
 tcp_v4_do_rcv+0xa25/0x12b0 net/ipv4/tcp_ipv4.c:1904
 sk_backlog_rcv include/net/sock.h:1177 [inline]
 __release_sock+0x285/0x3d0 net/core/sock.c:3213
 release_sock+0x75/0x210 net/core/sock.c:3795
 mptcp_connect+0x649/0x830 net/mptcp/protocol.c:3994
 __inet_stream_connect+0x25a/0xdd0 net/ipv4/af_inet.c:679
 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:750
 __sys_connect_file net/socket.c:2089 [inline]
 __sys_connect+0x315/0x450 net/socket.c:2108
 __do_sys_connect net/socket.c:2114 [inline]
 __se_sys_connect net/socket.c:2111 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2111
 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 24823:
 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:2540 [inline]
 slab_free mm/slub.c:6674 [inline]
 kfree+0x1bb/0x8f0 mm/slub.c:6886
 sk_prot_free net/core/sock.c:2284 [inline]
 __sk_destruct+0x626/0x880 net/core/sock.c:2384
 sock_put include/net/sock.h:1998 [inline]
 inet_csk_listen_stop+0x9cf/0xef0 net/ipv4/inet_connection_sock.c:1500
 mptcp_check_listen_stop+0x1c6/0x2b0 net/mptcp/protocol.c:3238
 __mptcp_close+0xf5/0xce0 net/mptcp/protocol.c:3253
 mptcp_close+0x28/0x1a0 net/mptcp/protocol.c:3319
 inet_release+0x143/0x190 net/ipv4/af_inet.c:437
 __sock_release net/socket.c:662 [inline]
 sock_close+0xc3/0x240 net/socket.c:1455
 __fput+0x45e/0xa80 fs/file_table.c:468
 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:44 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:75
 __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

The buggy address belongs to the object at ffff8880380c4000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 48 bytes inside of
 freed 4096-byte region [ffff8880380c4000, ffff8880380c5000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x380c0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe27140 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe27140 0000000000000000 dead000000000001
head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000e03001 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 69, tgid 69 (kworker/u8:4), ts 106665808808, free_ts 106549050902
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3a0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xaf8/0x13d0 mm/slub.c:4656
 __slab_alloc+0xc5/0x1f0 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __do_kmalloc_node mm/slub.c:5656 [inline]
 __kmalloc_node_track_caller_noprof+0x2b6/0x7f0 mm/slub.c:5768
 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608
 __alloc_skb+0x204/0x390 net/core/skbuff.c:690
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline]
 nsim_dev_trap_report_work+0x29f/0xbc0 drivers/net/netdevsim/dev.c:921
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
page last free pid 5858 tgid 5858 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xfd0/0x1160 mm/page_alloc.c:2973
 discard_slab mm/slub.c:3346 [inline]
 __put_partials+0x149/0x170 mm/slub.c:3886
 __slab_free+0x2af/0x330 mm/slub.c:5956
 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:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x188/0x6a0 mm/slub.c:5270
 getname_flags+0xb7/0x540 fs/namei.c:146
 getname include/linux/fs.h:2500 [inline]
 getname_maybe_null include/linux/fs.h:2507 [inline]
 vfs_fstatat+0x43/0x170 fs/stat.c:370
 __do_sys_newfstatat fs/stat.c:542 [inline]
 __se_sys_newfstatat fs/stat.c:536 [inline]
 __x64_sys_newfstatat+0x151/0x200 fs/stat.c:536
 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:
 ffff8880380c3f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880380c3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880380c4000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8880380c4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880380c4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================