kobject: kobject_add_internal failed for hci3:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci3: failed to register connection device ================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x1f9/0x2b0 net/bluetooth/l2cap_sock.c:1500 Read of size 8 at addr ffff888034df07a8 by task kworker/u9:3/5924 CPU: 1 UID: 0 PID: 5924 Comm: kworker/u9:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: hci3 hci_rx_work Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 l2cap_sock_new_connection_cb+0x1f9/0x2b0 net/bluetooth/l2cap_sock.c:1500 l2cap_connect_cfm+0x37a/0x1040 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2107 le_conn_complete_evt+0xfb8/0x1500 net/bluetooth/hci_event.c:5799 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5825 hci_event_func net/bluetooth/hci_event.c:7586 [inline] hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7643 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4099 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5924: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5650 [inline] __kmalloc_noprof+0x233/0x7d0 mm/slub.c:5662 kmalloc_noprof include/linux/slab.h:961 [inline] sk_prot_alloc+0xe7/0x220 net/core/sock.c:2239 sk_alloc+0x3a/0x370 net/core/sock.c:2295 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:151 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1897 [inline] l2cap_sock_new_connection_cb+0xe2/0x2b0 net/bluetooth/l2cap_sock.c:1485 l2cap_connect_cfm+0x37a/0x1040 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2107 le_conn_complete_evt+0xfb8/0x1500 net/bluetooth/hci_event.c:5799 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5825 hci_event_func net/bluetooth/hci_event.c:7586 [inline] hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7643 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4099 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 6561: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2543 [inline] slab_free mm/slub.c:6642 [inline] kfree+0x197/0x950 mm/slub.c:6849 sk_prot_free net/core/sock.c:2278 [inline] __sk_destruct+0x4e4/0x670 net/core/sock.c:2373 l2cap_sock_cleanup_listen+0xda/0x3e0 net/bluetooth/l2cap_sock.c:1465 l2cap_sock_release+0x6a/0x230 net/bluetooth/l2cap_sock.c:1426 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455 __fput+0x45b/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888034df0000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1960 bytes inside of freed 2048-byte region [ffff888034df0000, ffff888034df0800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34df0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0000d37c01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5829, tgid 5829 (syz-executor), ts 105983598332, free_ts 105930998295 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845 prep_new_page mm/page_alloc.c:1853 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3879 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3059 [inline] allocate_slab+0x96/0x350 mm/slub.c:3232 new_slab mm/slub.c:3286 [inline] ___slab_alloc+0xb10/0x1400 mm/slub.c:4655 __slab_alloc+0xc6/0x1f0 mm/slub.c:4778 __slab_alloc_node mm/slub.c:4854 [inline] slab_alloc_node mm/slub.c:5276 [inline] __do_kmalloc_node mm/slub.c:5649 [inline] __kmalloc_node_track_caller_noprof+0x2a8/0x7e0 mm/slub.c:5759 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:601 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] rtmsg_ifinfo_build_skb+0x84/0x260 net/core/rtnetlink.c:4400 rtmsg_ifinfo_event net/core/rtnetlink.c:4442 [inline] rtmsg_ifinfo+0x8c/0x1a0 net/core/rtnetlink.c:4451 register_netdevice+0x1746/0x1b10 net/core/dev.c:11346 __ip_tunnel_create+0x3e7/0x560 net/ipv4/ip_tunnel.c:268 ip_tunnel_init_net+0x2ba/0x800 net/ipv4/ip_tunnel.c:1147 vti_init_net+0x2f/0x100 net/ipv4/ip_vti.c:517 page last free pid 5832 tgid 5832 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xfb6/0x1140 mm/page_alloc.c:2901 discard_slab mm/slub.c:3330 [inline] __put_partials+0x149/0x170 mm/slub.c:3876 __slab_free+0x29e/0x370 mm/slub.c:5929 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4978 [inline] slab_alloc_node mm/slub.c:5288 [inline] __kmalloc_cache_noprof+0x181/0x6c0 mm/slub.c:5766 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] kset_create lib/kobject.c:965 [inline] kset_create_and_add+0x5a/0x180 lib/kobject.c:1008 register_queue_kobjects net/core/net-sysfs.c:2106 [inline] netdev_register_kobject+0x1a2/0x310 net/core/net-sysfs.c:2362 register_netdevice+0x12a0/0x1b10 net/core/dev.c:11294 __ip_tunnel_create+0x3e7/0x560 net/ipv4/ip_tunnel.c:268 ip_tunnel_init_net+0x2ba/0x800 net/ipv4/ip_tunnel.c:1147 ops_init+0x35c/0x5c0 net/core/net_namespace.c:137 setup_net+0xfe/0x320 net/core/net_namespace.c:445 copy_net_ns+0x34e/0x4e0 net/core/net_namespace.c:580 create_new_namespaces+0x3f3/0x720 kernel/nsproxy.c:110 Memory state around the buggy address: ffff888034df0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888034df0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888034df0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888034df0800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888034df0880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================