ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 kobject: kobject_add_internal failed for hci5:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci5: failed to register connection device ================================================================== BUG: KASAN: slab-use-after-free in l2cap_conn_ready net/bluetooth/l2cap_core.c:1616 [inline] BUG: KASAN: slab-use-after-free in l2cap_connect_cfm+0x86a/0x1390 net/bluetooth/l2cap_core.c:7368 Read of size 8 at addr ffff88804bac2500 by task kworker/u9:3/5800 CPU: 0 UID: 0 PID: 5800 Comm: kworker/u9:3 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: hci5 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:1616 [inline] l2cap_connect_cfm+0x86a/0x1390 net/bluetooth/l2cap_core.c:7368 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139 le_conn_complete_evt+0xf65/0x1430 net/bluetooth/hci_event.c:5847 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5873 hci_event_func net/bluetooth/hci_event.c:7781 [inline] hci_event_packet+0x7af/0x12c0 net/bluetooth/hci_event.c:7838 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5800: 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+0x3a6/0x690 mm/slub.c:5358 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] l2cap_chan_create+0x51/0x7a0 net/bluetooth/l2cap_core.c:445 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1931 [inline] l2cap_sock_new_connection_cb+0x182/0x2e0 net/bluetooth/l2cap_sock.c:1510 l2cap_connect_cfm+0x368/0x1390 net/bluetooth/l2cap_core.c:7351 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139 le_conn_complete_evt+0xf65/0x1430 net/bluetooth/hci_event.c:5847 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5873 hci_event_func net/bluetooth/hci_event.c:7781 [inline] hci_event_packet+0x7af/0x12c0 net/bluetooth/hci_event.c:7838 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 14144: 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:2692 [inline] slab_free mm/slub.c:6143 [inline] kfree+0x1c1/0x6c0 mm/slub.c:6461 l2cap_sock_cleanup_listen+0xf0/0x440 net/bluetooth/l2cap_sock.c:1493 l2cap_sock_release+0x6e/0x270 net/bluetooth/l2cap_sock.c:1451 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455 __fput+0x461/0xa90 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x11c3/0x1310 kernel/signal.c:2807 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:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88804bac2000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1280 bytes inside of freed 2048-byte region [ffff88804bac2000, ffff88804bac2800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4bac0 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 ffff88813fe1d000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe1d000 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea00012eb001 00000000ffffffff 00000000ffffffff head: 00000007f1673bb1 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 5796, tgid 5796 (kworker/1:3), ts 99711462028, free_ts 89718910811 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3269 [inline] allocate_slab+0x77/0x660 mm/slub.c:3458 new_slab mm/slub.c:3516 [inline] refill_objects+0x334/0x3c0 mm/slub.c:7153 refill_sheaf mm/slub.c:2818 [inline] __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4592 alloc_from_pcs mm/slub.c:4695 [inline] slab_alloc_node mm/slub.c:4829 [inline] __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5353 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] keypair_create drivers/net/wireguard/noise.c:100 [inline] wg_noise_handshake_begin_session+0xcc/0xbe0 drivers/net/wireguard/noise.c:827 wg_packet_send_handshake_response+0x13c/0x310 drivers/net/wireguard/send.c:96 wg_receive_handshake_packet drivers/net/wireguard/receive.c:154 [inline] wg_packet_handshake_receive_worker+0x72a/0x10a0 drivers/net/wireguard/receive.c:213 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page last free pid 5782 tgid 5782 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] free_unref_folios+0xe7b/0x1c70 mm/page_alloc.c:3040 folios_put_refs+0x56f/0x680 mm/swap.c:1002 free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423 __tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline] tlb_batch_pages_flush mm/mmu_gather.c:151 [inline] tlb_flush_mmu_free mm/mmu_gather.c:398 [inline] tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405 tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:530 unmap_region+0x2a5/0x330 mm/vma.c:488 vms_clear_ptes mm/vma.c:1284 [inline] vms_complete_munmap_vmas+0x493/0xc60 mm/vma.c:1326 do_vmi_align_munmap+0x3bd/0x4d0 mm/vma.c:1585 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1633 __vm_munmap+0x22c/0x3d0 mm/vma.c:3254 __do_sys_munmap mm/mmap.c:1078 [inline] __se_sys_munmap mm/mmap.c:1075 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1075 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88804bac2400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804bac2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804bac2500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804bac2580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804bac2600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================