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+0xe47/0x1010 net/bluetooth/l2cap_core.c:7305 Read of size 8 at addr ffff888061f41480 by task kworker/u9:6/5837 CPU: 0 UID: 0 PID: 5837 Comm: kworker/u9:6 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 lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 l2cap_conn_ready net/bluetooth/l2cap_core.c:1624 [inline] l2cap_connect_cfm+0xe47/0x1010 net/bluetooth/l2cap_core.c:7305 hci_connect_cfm include/net/bluetooth/hci_core.h:2131 [inline] le_conn_complete_evt+0x1991/0x1fa0 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x23c/0x3a0 net/bluetooth/hci_event.c:5847 hci_le_meta_evt+0x357/0x610 net/bluetooth/hci_event.c:7408 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x685/0x1210 net/bluetooth/hci_event.c:7773 hci_rx_work+0x2c9/0x1020 net/bluetooth/hci_core.c:4076 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Allocated by task 5837: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] l2cap_chan_create+0x44/0x930 net/bluetooth/l2cap_core.c:445 l2cap_sock_alloc.constprop.0+0xf5/0x1d0 net/bluetooth/l2cap_sock.c:1906 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1485 l2cap_connect_cfm+0x4f0/0x1010 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm include/net/bluetooth/hci_core.h:2131 [inline] le_conn_complete_evt+0x1991/0x1fa0 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x23c/0x3a0 net/bluetooth/hci_event.c:5847 hci_le_meta_evt+0x357/0x610 net/bluetooth/hci_event.c:7408 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x685/0x1210 net/bluetooth/hci_event.c:7773 hci_rx_work+0x2c9/0x1020 net/bluetooth/hci_core.c:4076 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 16154: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/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:6670 [inline] kfree+0x2f8/0x6e0 mm/slub.c:6878 l2cap_chan_destroy net/bluetooth/l2cap_core.c:491 [inline] kref_put include/linux/kref.h:65 [inline] l2cap_chan_put+0x1bb/0x310 net/bluetooth/l2cap_core.c:516 l2cap_sock_cleanup_listen+0x4d/0x2f0 net/bluetooth/l2cap_sock.c:1468 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1426 __sock_release+0xb3/0x270 net/socket.c:662 sock_close+0x1c/0x30 net/socket.c:1455 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 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+0xfb/0x540 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+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888061f41000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1152 bytes inside of freed 2048-byte region [ffff888061f41000, ffff888061f41800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61f40 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 ffff88813ff27000 ffffea00017c7000 0000000000000002 raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ff27000 ffffea00017c7000 0000000000000002 head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea000187d001 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 15428, tgid 15423 (syz.1.3091), ts 585592523395, free_ts 582940852324 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c3/0x430 mm/slub.c:3302 ___slab_alloc+0xe18/0x1c90 mm/slub.c:4656 __slab_alloc.constprop.0+0x63/0x110 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+0x4d6/0x930 mm/slub.c:5764 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:608 __alloc_skb+0x186/0x410 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xe0/0x860 net/core/skbuff.c:6712 sock_alloc_send_pskb+0x7f9/0x980 net/core/sock.c:2995 sock_alloc_send_skb include/net/sock.h:1885 [inline] llc_ui_sendmsg+0x39b/0x1540 net/llc/af_llc.c:970 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] sock_sendmsg+0x3cc/0x470 net/socket.c:765 splice_to_socket+0xaf4/0x1110 fs/splice.c:886 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1161 page last free pid 12713 tgid 12713 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943 page_frag_free+0x27f/0x2e0 mm/page_frag_cache.c:169 skb_free_frag include/linux/skbuff.h:3519 [inline] skb_free_head+0xa4/0x210 net/core/skbuff.c:1078 skb_release_data+0x795/0x9e0 net/core/skbuff.c:1107 skb_release_all net/core/skbuff.c:1182 [inline] __kfree_skb net/core/skbuff.c:1196 [inline] consume_skb net/core/skbuff.c:1428 [inline] consume_skb+0xbf/0x100 net/core/skbuff.c:1422 batadv_forw_packet_free+0x217/0x250 net/batman-adv/send.c:458 batadv_iv_send_outstanding_bat_ogm_packet+0x26d/0x920 net/batman-adv/bat_iv_ogm.c:1715 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Memory state around the buggy address: ffff888061f41380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888061f41400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888061f41480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888061f41500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888061f41580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ================================================================== BUG: KASAN: wild-memory-access in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: wild-memory-access in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] BUG: KASAN: wild-memory-access in l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline] BUG: KASAN: wild-memory-access in l2cap_conn_ready net/bluetooth/l2cap_core.c:1626 [inline] BUG: KASAN: wild-memory-access in l2cap_connect_cfm+0x80f/0x1010 net/bluetooth/l2cap_core.c:7305 Read of size 4 at addr deacfffffffffc8c by task kworker/u9:6/5837 CPU: 0 UID: 0 PID: 5837 Comm: kworker/u9:6 Tainted: G B L syzkaller #0 PREEMPT(full) Tainted: [B]=BAD_PAGE, [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 lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:194 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:200 instrument_atomic_read include/linux/instrumented.h:68 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline] l2cap_conn_ready net/bluetooth/l2cap_core.c:1626 [inline] l2cap_connect_cfm+0x80f/0x1010 net/bluetooth/l2cap_core.c:7305 hci_connect_cfm include/net/bluetooth/hci_core.h:2131 [inline] le_conn_complete_evt+0x1991/0x1fa0 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x23c/0x3a0 net/bluetooth/hci_event.c:5847 hci_le_meta_evt+0x357/0x610 net/bluetooth/hci_event.c:7408 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x685/0x1210 net/bluetooth/hci_event.c:7773 hci_rx_work+0x2c9/0x1020 net/bluetooth/hci_core.c:4076 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 ================================================================== Oops: general protection fault, probably for non-canonical address 0xfbd59bffffffff91: 0000 [#1] SMP KASAN NOPTI KASAN: maybe wild-memory-access in range [0xdeacfffffffffc88-0xdeacfffffffffc8f] CPU: 0 UID: 0 PID: 5837 Comm: kworker/u9:6 Tainted: G B L syzkaller #0 PREEMPT(full) Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: hci2 hci_rx_work RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] RIP: 0010:l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline] RIP: 0010:l2cap_conn_ready net/bluetooth/l2cap_core.c:1626 [inline] RIP: 0010:l2cap_connect_cfm+0x816/0x1010 net/bluetooth/l2cap_core.c:7305 Code: 80 fb ff ff 49 39 c5 0f 84 29 01 00 00 e8 02 51 46 f7 49 8d 6f 0c be 04 00 00 00 48 89 ef e8 51 39 af f7 48 89 e8 48 c1 e8 03 <0f> b6 14 18 48 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 27 RSP: 0018:ffffc9000401f7d8 EFLAGS: 00010213 RAX: 1bd59fffffffff91 RBX: dffffc0000000000 RCX: ffffc9001ca61000 RDX: 0000000000100000 RSI: ffffffff8227a027 RDI: 0000000000000007 RBP: deacfffffffffc8c R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 3d3d3d3d3d3d3d3d R12: ffff88802139403d R13: ffff8880551dbac0 R14: 0000000000000080 R15: deacfffffffffc80 FS: 0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c34915a CR3: 000000002a6cf000 CR4: 0000000000350ef0 Call Trace: hci_connect_cfm include/net/bluetooth/hci_core.h:2131 [inline] le_conn_complete_evt+0x1991/0x1fa0 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x23c/0x3a0 net/bluetooth/hci_event.c:5847 hci_le_meta_evt+0x357/0x610 net/bluetooth/hci_event.c:7408 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x685/0x1210 net/bluetooth/hci_event.c:7773 hci_rx_work+0x2c9/0x1020 net/bluetooth/hci_core.c:4076 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] RIP: 0010:l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline] RIP: 0010:l2cap_conn_ready net/bluetooth/l2cap_core.c:1626 [inline] RIP: 0010:l2cap_connect_cfm+0x816/0x1010 net/bluetooth/l2cap_core.c:7305 Code: 80 fb ff ff 49 39 c5 0f 84 29 01 00 00 e8 02 51 46 f7 49 8d 6f 0c be 04 00 00 00 48 89 ef e8 51 39 af f7 48 89 e8 48 c1 e8 03 <0f> b6 14 18 48 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 27 RSP: 0018:ffffc9000401f7d8 EFLAGS: 00010213 RAX: 1bd59fffffffff91 RBX: dffffc0000000000 RCX: ffffc9001ca61000 RDX: 0000000000100000 RSI: ffffffff8227a027 RDI: 0000000000000007 RBP: deacfffffffffc8c R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 3d3d3d3d3d3d3d3d R12: ffff88802139403d R13: ffff8880551dbac0 R14: 0000000000000080 R15: deacfffffffffc80 FS: 0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c34915a CR3: 000000002a6cf000 CR4: 0000000000350ef0 ---------------- Code disassembly (best guess), 4 bytes skipped: 0: 49 39 c5 cmp %rax,%r13 3: 0f 84 29 01 00 00 je 0x132 9: e8 02 51 46 f7 call 0xf7465110 e: 49 8d 6f 0c lea 0xc(%r15),%rbp 12: be 04 00 00 00 mov $0x4,%esi 17: 48 89 ef mov %rbp,%rdi 1a: e8 51 39 af f7 call 0xf7af3970 1f: 48 89 e8 mov %rbp,%rax 22: 48 c1 e8 03 shr $0x3,%rax * 26: 0f b6 14 18 movzbl (%rax,%rbx,1),%edx <-- trapping instruction 2a: 48 89 e8 mov %rbp,%rax 2d: 83 e0 07 and $0x7,%eax 30: 83 c0 03 add $0x3,%eax 33: 38 d0 cmp %dl,%al 35: 7c 08 jl 0x3f 37: 84 d2 test %dl,%dl 39: 0f .byte 0xf 3a: 85 27 test %esp,(%rdi)