kobject_add_internal failed for hci0:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci0: failed to register connection device ================================================================== BUG: KASAN: use-after-free in l2cap_conn_ready net/bluetooth/l2cap_core.c:1758 [inline] BUG: KASAN: use-after-free in l2cap_connect_cfm+0x6ff/0x10d0 net/bluetooth/l2cap_core.c:8320 Read of size 8 at addr ffff88807bfde488 by task kworker/u5:1/4264 CPU: 0 PID: 4264 Comm: kworker/u5:1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: hci0 hci_rx_work Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 l2cap_conn_ready net/bluetooth/l2cap_core.c:1758 [inline] l2cap_connect_cfm+0x6ff/0x10d0 net/bluetooth/l2cap_core.c:8320 hci_connect_cfm include/net/bluetooth/hci_core.h:1505 [inline] le_conn_complete_evt+0xdaf/0x1590 net/bluetooth/hci_event.c:5439 hci_le_conn_complete_evt net/bluetooth/hci_event.c:5464 [inline] hci_le_meta_evt+0x289/0x3b80 net/bluetooth/hci_event.c:6186 hci_event_packet+0xe05/0x12f0 net/bluetooth/hci_event.c:6535 hci_rx_work+0x255/0xa10 net/bluetooth/hci_core.c:5160 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 4264: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522 kmalloc include/linux/slab.h:604 [inline] kzalloc include/linux/slab.h:735 [inline] l2cap_chan_create+0x4c/0x730 net/bluetooth/l2cap_core.c:469 l2cap_sock_alloc+0x13a/0x200 net/bluetooth/l2cap_sock.c:1882 l2cap_sock_new_connection_cb+0xd1/0x1c0 net/bluetooth/l2cap_sock.c:1479 l2cap_connect_cfm+0x35d/0x10d0 net/bluetooth/l2cap_core.c:8303 hci_connect_cfm include/net/bluetooth/hci_core.h:1505 [inline] le_conn_complete_evt+0xdaf/0x1590 net/bluetooth/hci_event.c:5439 hci_le_conn_complete_evt net/bluetooth/hci_event.c:5464 [inline] hci_le_meta_evt+0x289/0x3b80 net/bluetooth/hci_event.c:6186 hci_event_packet+0xe05/0x12f0 net/bluetooth/hci_event.c:6535 hci_rx_work+0x255/0xa10 net/bluetooth/hci_core.c:5160 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Freed by task 4357: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 l2cap_sock_cleanup_listen+0xea/0x270 net/bluetooth/l2cap_sock.c:1462 l2cap_sock_release+0x66/0x1e0 net/bluetooth/l2cap_sock.c:1420 __sock_release net/socket.c:649 [inline] sock_close+0xd5/0x240 net/socket.c:1336 __fput+0x234/0x930 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff88807bfde000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1160 bytes inside of 2048-byte region [ffff88807bfde000, ffff88807bfde800) The buggy address belongs to the page: page:ffffea0001eff600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7bfd8 head:ffffea0001eff600 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888016842000 raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x152a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 4264, ts 80764463869, free_ts 80463257214 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3250 kmalloc include/linux/slab.h:604 [inline] kzalloc include/linux/slab.h:735 [inline] l2cap_chan_create+0x4c/0x730 net/bluetooth/l2cap_core.c:469 l2cap_sock_alloc+0x13a/0x200 net/bluetooth/l2cap_sock.c:1882 l2cap_sock_new_connection_cb+0xd1/0x1c0 net/bluetooth/l2cap_sock.c:1479 l2cap_connect_cfm+0x35d/0x10d0 net/bluetooth/l2cap_core.c:8303 hci_connect_cfm include/net/bluetooth/hci_core.h:1505 [inline] le_conn_complete_evt+0xdaf/0x1590 net/bluetooth/hci_event.c:5439 hci_le_conn_complete_evt net/bluetooth/hci_event.c:5464 [inline] hci_le_meta_evt+0x289/0x3b80 net/bluetooth/hci_event.c:6186 hci_event_packet+0xe05/0x12f0 net/bluetooth/hci_event.c:6535 hci_rx_work+0x255/0xa10 net/bluetooth/hci_core.c:5160 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x94/0x280 mm/page_alloc.c:3396 free_slab mm/slub.c:2020 [inline] discard_slab mm/slub.c:2026 [inline] __unfreeze_partials+0x1a5/0x200 mm/slub.c:2512 put_cpu_partial+0x12d/0x190 mm/slub.c:2592 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x100/0x290 mm/slub.c:3238 ptlock_alloc+0x1c/0x60 mm/memory.c:5556 ptlock_init include/linux/mm.h:2241 [inline] pgtable_pte_page_ctor include/linux/mm.h:2268 [inline] __pte_alloc_one include/asm-generic/pgalloc.h:66 [inline] pte_alloc_one+0xc5/0x2f0 arch/x86/mm/pgtable.c:33 do_fault_around mm/memory.c:4237 [inline] do_read_fault mm/memory.c:4258 [inline] do_fault mm/memory.c:4392 [inline] handle_pte_fault mm/memory.c:4650 [inline] __handle_mm_fault mm/memory.c:4785 [inline] handle_mm_fault+0x2518/0x43c0 mm/memory.c:4883 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1445 [inline] exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 Memory state around the buggy address: ffff88807bfde380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807bfde400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807bfde480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807bfde500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807bfde580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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