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:1623 [inline]
BUG: KASAN: slab-use-after-free in l2cap_connect_cfm+0x574/0xd40 net/bluetooth/l2cap_core.c:7281
Read of size 8 at addr ffff0000da6d6480 by task kworker/u9:4/6526

CPU: 0 UID: 0 PID: 6526 Comm: kworker/u9:4 Not tainted 6.16.0-rc2-syzkaller-g9aa9b43d689e #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci4 hci_rx_work
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:501 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xa8/0x254 mm/kasan/report.c:408
 print_report+0x68/0x84 mm/kasan/report.c:521
 kasan_report+0xb0/0x110 mm/kasan/report.c:634
 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1623 [inline]
 l2cap_connect_cfm+0x574/0xd40 net/bluetooth/l2cap_core.c:7281
 hci_connect_cfm+0x98/0x134 include/net/bluetooth/hci_core.h:2054
 le_conn_complete_evt+0x9f4/0xe84 net/bluetooth/hci_event.c:5791
 hci_le_conn_complete_evt+0x114/0x3f8 net/bluetooth/hci_event.c:5817
 hci_le_meta_evt+0x2cc/0x4b0 net/bluetooth/hci_event.c:7200
 hci_event_func net/bluetooth/hci_event.c:7508 [inline]
 hci_event_packet+0x60c/0xe9c net/bluetooth/hci_event.c:7565
 hci_rx_work+0x320/0xb18 net/bluetooth/hci_core.c:4044
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847

Allocated by task 6526:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x2a4/0x3fc mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 l2cap_chan_create+0x58/0x698 net/bluetooth/l2cap_core.c:445
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1900 [inline]
 l2cap_sock_new_connection_cb+0x164/0x284 net/bluetooth/l2cap_sock.c:1482
 l2cap_connect_cfm+0x2d8/0xd40 net/bluetooth/l2cap_core.c:7264
 hci_connect_cfm+0x98/0x134 include/net/bluetooth/hci_core.h:2054
 le_conn_complete_evt+0x9f4/0xe84 net/bluetooth/hci_event.c:5791
 hci_le_conn_complete_evt+0x114/0x3f8 net/bluetooth/hci_event.c:5817
 hci_le_meta_evt+0x2cc/0x4b0 net/bluetooth/hci_event.c:7200
 hci_event_func net/bluetooth/hci_event.c:7508 [inline]
 hci_event_packet+0x60c/0xe9c net/bluetooth/hci_event.c:7565
 hci_rx_work+0x320/0xb18 net/bluetooth/hci_core.c:4044
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847

Freed by task 8896:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x68/0x88 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x17c/0x474 mm/slub.c:4842
 l2cap_chan_destroy net/bluetooth/l2cap_core.c:491 [inline]
 kref_put include/linux/kref.h:65 [inline]
 l2cap_chan_put+0x174/0x24c net/bluetooth/l2cap_core.c:515
 l2cap_sock_cleanup_listen+0x104/0x28c net/bluetooth/l2cap_sock.c:1465
 l2cap_sock_release+0x5c/0x1ac net/bluetooth/l2cap_sock.c:1425
 __sock_release net/socket.c:647 [inline]
 sock_close+0xa0/0x1e4 net/socket.c:1391
 __fput+0x340/0x75c fs/file_table.c:465
 ____fput+0x20/0x58 fs/file_table.c:493
 task_work_run+0x1dc/0x260 kernel/task_work.c:227
 get_signal+0x112c/0x12f8 kernel/signal.c:2807
 do_signal+0x274/0x4438 arch/arm64/kernel/signal.c:1615
 do_notify_resume+0xac/0x1ec arch/arm64/kernel/entry-common.c:148
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xb4/0x17c arch/arm64/kernel/entry-common.c:768
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

The buggy address belongs to the object at ffff0000da6d6000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1152 bytes inside of
 freed 2048-byte region [ffff0000da6d6000, ffff0000da6d6800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11a6d0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000040 ffff0000c0002000 fffffdffc320d800 dead000000000002
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 05ffc00000000040 ffff0000c0002000 fffffdffc320d800 dead000000000002
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 05ffc00000000003 fffffdffc369b401 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000da6d6380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000da6d6400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000da6d6480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff0000da6d6500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000da6d6580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Unable to handle kernel paging request at virtual address fbd51fffffffff91
KASAN: maybe wild-memory-access in range [0xdeacfffffffffc88-0xdeacfffffffffc8f]
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[fbd51fffffffff91] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 6526 Comm: kworker/u9:4 Tainted: G    B               6.16.0-rc2-syzkaller-g9aa9b43d689e #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci4 hci_rx_work
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
pc : atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
pc : l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline]
pc : l2cap_conn_ready net/bluetooth/l2cap_core.c:1625 [inline]
pc : l2cap_connect_cfm+0x50c/0xd40 net/bluetooth/l2cap_core.c:7281
lr : instrument_atomic_read include/linux/instrumented.h:68 [inline]
lr : atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
lr : l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline]
lr : l2cap_conn_ready net/bluetooth/l2cap_core.c:1625 [inline]
lr : l2cap_connect_cfm+0x500/0xd40 net/bluetooth/l2cap_core.c:7281
sp : ffff8000a3c17520
x29: ffff8000a3c175c0 x28: dfff800000000000 x27: 1fffe000197dc807
x26: ffff0000d0c5e01a x25: 0000000000000080 x24: deacfffffffffc8c
x23: 1fffe0001a18bc03 x22: dead000000000100 x21: ffff0000d0c5e2c0
x20: ffff0000cbee403d x19: ffff0000d0c5e000 x18: 1fffe000337dc876
x17: 0000000000000000 x16: ffff80008ae33808 x15: 0000000000000001
x14: 1ffff000125d0af8 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000100000 x10: fffffffffffffff8 x9 : 0000000000000007
x8 : 1bd59fffffffff91 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000a3c16d98 x4 : ffff80008f727060 x3 : ffff80008a194f1c
x2 : 0000000000000000 x1 : 0000000000000004 x0 : 0000000000000001
Call trace:
 raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] (P)
 atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] (P)
 l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline] (P)
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1625 [inline] (P)
 l2cap_connect_cfm+0x50c/0xd40 net/bluetooth/l2cap_core.c:7281 (P)
 hci_connect_cfm+0x98/0x134 include/net/bluetooth/hci_core.h:2054
 le_conn_complete_evt+0x9f4/0xe84 net/bluetooth/hci_event.c:5791
 hci_le_conn_complete_evt+0x114/0x3f8 net/bluetooth/hci_event.c:5817
 hci_le_meta_evt+0x2cc/0x4b0 net/bluetooth/hci_event.c:7200
 hci_event_func net/bluetooth/hci_event.c:7508 [inline]
 hci_event_packet+0x60c/0xe9c net/bluetooth/hci_event.c:7565
 hci_rx_work+0x320/0xb18 net/bluetooth/hci_core.c:4044
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847
Code: 9780946b d343ff08 12000b09 11000d29 (38fc6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	9780946b 	bl	0xfffffffffe0251ac
   4:	d343ff08 	lsr	x8, x24, #3
   8:	12000b09 	and	w9, w24, #0x7
   c:	11000d29 	add	w9, w9, #0x3
* 10:	38fc6908 	ldrsb	w8, [x8, x28] <-- trapping instruction