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BUG: KASAN: use-after-free in __list_del_entry_valid_or_report+0x92/0x190 lib/list_debug.c:62
Read of size 8 at addr ffff888058f9d780 by task syz.3.1352/11124

CPU: 1 UID: 0 PID: 11124 Comm: syz.3.1352 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 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]
 bt_accept_unlink+0x39/0x260 net/bluetooth/af_bluetooth.c:259
 l2cap_sock_teardown_cb+0x17e/0x490 net/bluetooth/l2cap_sock.c:1640
 l2cap_chan_del+0xb5/0x610 net/bluetooth/l2cap_core.c:656
 l2cap_conn_del+0x33d/0x570 net/bluetooth/l2cap_core.c:1802
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]
 hci_conn_hash_flush+0x10d/0x260 net/bluetooth/hci_conn.c:2650
 hci_dev_close_sync+0x821/0x10e0 net/bluetooth/hci_sync.c:5368
 hci_dev_do_close net/bluetooth/hci_core.c:502 [inline]
 hci_unregister_dev+0x21a/0x5a0 net/bluetooth/hci_core.c:2716
 vhci_release+0x155/0x1b0 drivers/bluetooth/hci_vhci.c:690
 __fput+0x461/0xa70 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x70f/0x22c0 kernel/exit.c:975
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117
 get_signal+0x1284/0x1330 kernel/signal.c:3037
 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+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffad213c819
Code: Unable to access opcode bytes at 0x7ffad213c7ef.
RSP: 002b:00007ffad0396028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007ffad23b5fa0 RCX: 00007ffad213c819
RDX: 0000200000000040 RSI: 00000000400454ca RDI: 0000000000000004
RBP: 00007ffad21d2c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffad23b6038 R14: 00007ffad23b5fa0 R15: 00007ffc539cd158
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x58f9d
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 10828, tgid 10825 (syz.5.1274), ts 566559084093, free_ts 599030768496
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7251
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __do_kmalloc_node mm/slub.c:5294 [inline]
 __kmalloc_node_track_caller_noprof+0x60b/0x7e0 mm/slub.c:5403
 kmalloc_reserve net/core/skbuff.c:635 [inline]
 pskb_expand_head+0x230/0x1390 net/core/skbuff.c:2302
 netlink_trim+0x1b3/0x2c0 net/netlink/af_netlink.c:1299
 netlink_broadcast_filtered+0x80/0xea0 net/netlink/af_netlink.c:1512
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
 netif_state_change+0x297/0x3a0 net/core/dev.c:1605
 do_setlink+0xbf6/0x4590 net/core/rtnetlink.c:3427
 rtnl_group_changelink net/core/rtnetlink.c:3812 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3980 [inline]
 rtnl_newlink+0x14ca/0x1bb0 net/core/rtnetlink.c:4108
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6994
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
page last free pid 5818 tgid 5818 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xf9b/0x10f0 mm/page_alloc.c:2943
 __slab_free+0x252/0x2a0 mm/slub.c:5608
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 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:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 kmem_cache_alloc_node_noprof+0x22a/0x6e0 mm/slub.c:4950
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 alloc_skb_fclone include/linux/skbuff.h:1433 [inline]
 tcp_stream_alloc_skb+0x3f/0x5c0 net/ipv4/tcp.c:935
 tso_fragment net/ipv4/tcp_output.c:2407 [inline]
 tcp_write_xmit+0x12f7/0x6430 net/ipv4/tcp_output.c:3044
 tcp_sendmsg_locked+0x2d7b/0x5370 net/ipv4/tcp.c:1398
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1455
 sock_sendmsg_nosec net/socket.c:786 [inline]
 __sock_sendmsg net/socket.c:801 [inline]
 sock_write_iter+0x40c/0x4f0 net/socket.c:1253
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x629/0xba0 fs/read_write.c:688
 ksys_write+0x156/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888058f9d680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888058f9d700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888058f9d780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888058f9d800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888058f9d880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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