syzbot

 </TASK>
kobject: kobject_add_internal failed for hci1:201 with -EEXIST, don't try to register things with the same name in the same directory.
Bluetooth: hci1: failed to register connection device
==================================================================
BUG: KASAN: slab-use-after-free in l2cap_sock_ready_cb+0x16a/0x170 net/bluetooth/l2cap_sock.c:1684
Read of size 8 at addr ffff88804d7fe188 by task kworker/u9:3/5825

CPU: 0 UID: 0 PID: 5825 Comm: kworker/u9:3 Not tainted 6.15.0-syzkaller-08297-ge0797d3b91de #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 __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:408 [inline]
 print_report+0xcd/0x680 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 l2cap_sock_ready_cb+0x16a/0x170 net/bluetooth/l2cap_sock.c:1684
 l2cap_chan_ready net/bluetooth/l2cap_core.c:1246 [inline]
 l2cap_le_start+0x1ea/0xe40 net/bluetooth/l2cap_core.c:1375
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1628 [inline]
 l2cap_connect_cfm+0x8f4/0xf80 net/bluetooth/l2cap_core.c:7280
 hci_connect_cfm include/net/bluetooth/hci_core.h:2050 [inline]
 le_conn_complete_evt+0x1662/0x1d70 net/bluetooth/hci_event.c:5791
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5817
 hci_le_meta_evt+0x354/0x5e0 net/bluetooth/hci_event.c:7200
 hci_event_func net/bluetooth/hci_event.c:7508 [inline]
 hci_event_packet+0x685/0x11c0 net/bluetooth/hci_event.c:7565
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4036
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 7402:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4339
 kmalloc_noprof include/linux/slab.h:909 [inline]
 sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2247
 sk_alloc+0x36/0xc20 net/core/sock.c:2303
 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc.constprop.0+0x33/0x1d0 net/bluetooth/l2cap_sock.c:1891
 l2cap_sock_create+0x123/0x1f0 net/bluetooth/l2cap_sock.c:1933
 bt_sock_create+0x185/0x350 net/bluetooth/af_bluetooth.c:135
 __sock_create+0x335/0x8d0 net/socket.c:1541
 sock_create net/socket.c:1599 [inline]
 __sys_socket_create net/socket.c:1636 [inline]
 __sys_socket+0x14d/0x260 net/socket.c:1683
 __do_sys_socket net/socket.c:1697 [inline]
 __se_sys_socket net/socket.c:1695 [inline]
 __x64_sys_socket+0x72/0xb0 net/socket.c:1695
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 7402:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free mm/slub.c:4642 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4841
 sk_prot_free net/core/sock.c:2286 [inline]
 __sk_destruct+0x740/0x980 net/core/sock.c:2381
 sk_destruct+0xc2/0xf0 net/core/sock.c:2409
 __sk_free+0xf4/0x3e0 net/core/sock.c:2420
 sk_free+0x6a/0x90 net/core/sock.c:2431
 sock_put include/net/sock.h:1960 [inline]
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1265 [inline]
 l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1250
 l2cap_sock_release+0x189/0x210 net/bluetooth/l2cap_sock.c:1435
 __sock_release+0xb3/0x270 net/socket.c:647
 sock_close+0x1c/0x30 net/socket.c:1391
 __fput+0x3ff/0xb70 fs/file_table.c:465
 task_work_run+0x150/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88804d7fe000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 392 bytes inside of
 freed 2048-byte region [ffff88804d7fe000, ffff88804d7fe800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4d7f8
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 ffff88801b442000 0000000000000000 0000000000000001
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b442000 0000000000000000 0000000000000001
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea000135fe01 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 7100, tgid 7099 (syz.1.300), ts 159696168930, free_ts 15929276262
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1710
 prep_new_page mm/page_alloc.c:1718 [inline]
 get_page_from_freelist+0x135c/0x3950 mm/page_alloc.c:3680
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 copy_verifier_state kernel/bpf/verifier.c:1763 [inline]
 copy_verifier_state+0xbc8/0xfa0 kernel/bpf/verifier.c:1730
 is_state_visited kernel/bpf/verifier.c:19301 [inline]
 do_check kernel/bpf/verifier.c:19463 [inline]
 do_check_common+0x541e/0xc0e0 kernel/bpf/verifier.c:22808
 do_check_main kernel/bpf/verifier.c:22899 [inline]
 bpf_check+0x83f0/0xbc50 kernel/bpf/verifier.c:24065
 bpf_prog_load+0xe41/0x2490 kernel/bpf/syscall.c:2972
 __sys_bpf+0x433c/0x4d80 kernel/bpf/syscall.c:5836
 __do_sys_bpf kernel/bpf/syscall.c:5943 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5941 [inline]
 __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5941
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1254 [inline]
 __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2717
 __free_pages mm/page_alloc.c:5082 [inline]
 free_contig_range+0x183/0x4b0 mm/page_alloc.c:6938
 destroy_args+0x7f6/0xa60 mm/debug_vm_pgtable.c:1017
 debug_vm_pgtable+0x13c4/0x2d90 mm/debug_vm_pgtable.c:1397
 do_one_initcall+0x120/0x6e0 init/main.c:1257
 do_initcall_level init/main.c:1319 [inline]
 do_initcalls init/main.c:1335 [inline]
 do_basic_setup init/main.c:1354 [inline]
 kernel_init_freeable+0x5c2/0x900 init/main.c:1567
 kernel_init+0x1c/0x2b0 init/main.c:1457
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88804d7fe080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804d7fe100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88804d7fe180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88804d7fe200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804d7fe280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================