kobject: kobject_add_internal failed for hci2:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci2: failed to register connection device ================================================================== BUG: KASAN: slab-use-after-free in l2cap_conn_ready net/bluetooth/l2cap_core.c:1624 [inline] BUG: KASAN: slab-use-after-free in l2cap_connect_cfm+0x87d/0x13e0 net/bluetooth/l2cap_core.c:7305 Read of size 8 at addr ffff88807ddbb480 by task kworker/u9:4/5836 CPU: 1 UID: 0 PID: 5836 Comm: kworker/u9:4 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: hci2 hci_rx_work Call Trace: 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 l2cap_conn_ready net/bluetooth/l2cap_core.c:1624 [inline] l2cap_connect_cfm+0x87d/0x13e0 net/bluetooth/l2cap_core.c:7305 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2131 le_conn_complete_evt+0xf65/0x1430 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5847 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x7af/0x12c0 net/bluetooth/hci_event.c:7773 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4076 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 Allocated by task 5836: 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] __kmalloc_cache_noprof+0x3d1/0x6e0 mm/slub.c:5780 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] l2cap_chan_create+0x51/0x790 net/bluetooth/l2cap_core.c:445 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1906 [inline] l2cap_sock_new_connection_cb+0x182/0x2e0 net/bluetooth/l2cap_sock.c:1485 l2cap_connect_cfm+0x368/0x13e0 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2131 le_conn_complete_evt+0xf65/0x1430 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5847 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x7af/0x12c0 net/bluetooth/hci_event.c:7773 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4076 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 Freed by task 9953: 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+0x1be/0x650 mm/slub.c:6882 l2cap_sock_cleanup_listen+0xf0/0x440 net/bluetooth/l2cap_sock.c:1468 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+0x44f/0xa70 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 ffff88807ddbb000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1152 bytes inside of freed 2048-byte region [ffff88807ddbb000, ffff88807ddbb800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7ddb8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813fe27000 0000000000000000 dead000000000001 raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe27000 0000000000000000 dead000000000001 head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001f76e01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 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 5820, tgid 5820 (syz-executor), ts 93800110178, free_ts 93734130202 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+0x24dc/0x2580 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240 alloc_pages_mpol+0x232/0x4a0 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+0xd82/0x1760 mm/slub.c:4656 __slab_alloc+0x65/0x100 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_noprof+0x5bc/0x7f0 mm/slub.c:5663 kmalloc_node_noprof include/linux/slab.h:987 [inline] qdisc_alloc+0x92/0x900 net/sched/sch_generic.c:951 qdisc_create_dflt+0x8e/0x4c0 net/sched/sch_generic.c:1008 attach_one_default_qdisc net/sched/sch_generic.c:1174 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2680 [inline] attach_default_qdiscs net/sched/sch_generic.c:1192 [inline] dev_activate+0x378/0x1150 net/sched/sch_generic.c:1251 __dev_open+0x67a/0x830 net/core/dev.c:1705 __dev_change_flags+0x1f7/0x690 net/core/dev.c:9749 netif_change_flags+0x88/0x1a0 net/core/dev.c:9812 do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3158 rtnl_changelink net/core/rtnetlink.c:3776 [inline] __rtnl_newlink net/core/rtnetlink.c:3935 [inline] rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4072 page last free pid 12 tgid 12 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xbf8/0xd70 mm/page_alloc.c:2973 __slab_free+0x2ce/0x320 mm/slub.c:6008 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] __kmalloc_cache_noprof+0x36f/0x6e0 mm/slub.c:5775 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] ipv6_add_addr+0x55e/0x1100 net/ipv6/addrconf.c:1120 addrconf_add_linklocal+0x20c/0x460 net/ipv6/addrconf.c:3311 addrconf_addr_gen+0x2f8/0x360 net/ipv6/addrconf.c:3442 addrconf_notify+0xb1e/0x1050 net/ipv6/addrconf.c:3740 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 netif_state_change+0x27d/0x3a0 net/core/dev.c:1597 linkwatch_do_dev+0x117/0x170 net/core/link_watch.c:186 __linkwatch_run_queue+0x572/0x7f0 net/core/link_watch.c:244 linkwatch_event+0x4c/0x60 net/core/link_watch.c:304 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 Memory state around the buggy address: ffff88807ddbb380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807ddbb400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807ddbb480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807ddbb500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807ddbb580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================