kobject: kobject_add_internal failed for hci4:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci4: 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+0x6d0/0x10e0 net/bluetooth/l2cap_core.c:7305 Read of size 8 at addr ffff88802072d480 by task kworker/u9:1/5142 CPU: 1 UID: 0 PID: 5142 Comm: kworker/u9:1 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: hci4 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_conn_ready net/bluetooth/l2cap_core.c:1624 [inline] l2cap_connect_cfm+0x6d0/0x10e0 net/bluetooth/l2cap_core.c:7305 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2131 le_conn_complete_evt+0xf65/0x1420 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x187/0x480 net/bluetooth/hci_event.c:5847 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x78f/0x1260 net/bluetooth/hci_event.c:7773 hci_rx_work+0x3ee/0x1060 net/bluetooth/hci_core.c:4076 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Allocated by task 5142: 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:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5776 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+0x367/0x10e0 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2131 le_conn_complete_evt+0xf65/0x1420 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x187/0x480 net/bluetooth/hci_event.c:5847 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x78f/0x1260 net/bluetooth/hci_event.c:7773 hci_rx_work+0x3ee/0x1060 net/bluetooth/hci_core.c:4076 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 18958: 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:584 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:2540 [inline] slab_free mm/slub.c:6668 [inline] kfree+0x1c0/0x660 mm/slub.c:6876 l2cap_sock_cleanup_listen+0xf0/0x450 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+0x44c/0xa70 fs/file_table.c:468 task_work_run+0x1d4/0x260 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+0xff/0x4f0 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+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802072d000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1152 bytes inside of freed 2048-byte region [ffff88802072d000, ffff88802072d800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802072a000 pfn:0x20728 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ffa7000 ffffea00014fd800 0000000000000002 raw: ffff88802072a000 0000000080080006 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ffa7000 ffffea00014fd800 0000000000000002 head: ffff88802072a000 0000000080080006 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea000081ca01 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 18350, tgid 18350 (syz-executor), ts 1539148546579, free_ts 1538722960136 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xf2b/0x1960 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_track_caller_noprof+0x5d4/0x820 mm/slub.c:5764 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608 pskb_expand_head+0x19d/0x1160 net/core/skbuff.c:2282 netlink_trim+0x1b3/0x2c0 net/netlink/af_netlink.c:1299 netlink_broadcast_filtered+0xd6/0x1000 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 __dev_notify_flags+0xf4/0x2e0 net/core/dev.c:9769 rtnl_configure_link net/core/rtnetlink.c:3606 [inline] rtnl_newlink_create+0x61c/0xb00 net/core/rtnetlink.c:3850 __rtnl_newlink net/core/rtnetlink.c:3957 [inline] rtnl_newlink+0x16e7/0x1c90 net/core/rtnetlink.c:4072 page last free pid 5808 tgid 5808 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x146/0x170 mm/slub.c:3886 put_cpu_partial+0x1f2/0x2d0 mm/slub.c:3961 __slab_free+0x288/0x2a0 mm/slub.c:5952 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:349 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5315 __alloc_skb+0x255/0x430 net/core/skbuff.c:679 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x3d/0x350 net/ipv4/tcp.c:910 tcp_sendmsg_locked+0x1ab8/0x5520 net/ipv4/tcp.c:1217 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1412 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x19c/0x270 net/socket.c:742 sock_write_iter+0x279/0x360 net/socket.c:1195 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 Memory state around the buggy address: ffff88802072d380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802072d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802072d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802072d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802072d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================