syzbot

 </TASK>
kobject: 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: slab-use-after-free in l2cap_sock_new_connection_cb+0x1f9/0x2b0 net/bluetooth/l2cap_sock.c:1500
Read of size 8 at addr ffff8880348367a0 by task kworker/u9:4/5811

CPU: 1 UID: 0 PID: 5811 Comm: kworker/u9:4 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 l2cap_sock_new_connection_cb+0x1f9/0x2b0 net/bluetooth/l2cap_sock.c:1500
 l2cap_connect_cfm+0x37a/0x1040 net/bluetooth/l2cap_core.c:7287
 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2106
 le_conn_complete_evt+0xfb8/0x1500 net/bluetooth/hci_event.c:5785
 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5811
 hci_event_func net/bluetooth/hci_event.c:7556 [inline]
 hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7613
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4099
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5811:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5627 [inline]
 __kmalloc_noprof+0x233/0x7d0 mm/slub.c:5639
 kmalloc_noprof include/linux/slab.h:961 [inline]
 sk_prot_alloc+0xe7/0x220 net/core/sock.c:2239
 sk_alloc+0x3a/0x370 net/core/sock.c:2295
 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1897 [inline]
 l2cap_sock_new_connection_cb+0xe2/0x2b0 net/bluetooth/l2cap_sock.c:1485
 l2cap_connect_cfm+0x37a/0x1040 net/bluetooth/l2cap_core.c:7287
 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2106
 le_conn_complete_evt+0xfb8/0x1500 net/bluetooth/hci_event.c:5785
 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5811
 hci_event_func net/bluetooth/hci_event.c:7556 [inline]
 hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7613
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4099
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 12470:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2523 [inline]
 slab_free mm/slub.c:6611 [inline]
 kfree+0x197/0x950 mm/slub.c:6818
 sk_prot_free net/core/sock.c:2278 [inline]
 __sk_destruct+0x4e4/0x670 net/core/sock.c:2373
 l2cap_sock_cleanup_listen+0xda/0x3e0 net/bluetooth/l2cap_sock.c:1465
 l2cap_sock_release+0x6a/0x230 net/bluetooth/l2cap_sock.c:1426
 __sock_release net/socket.c:662 [inline]
 sock_close+0xc3/0x240 net/socket.c:1455
 __fput+0x45b/0xa80 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 get_signal+0x11c4/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888034836000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1952 bytes inside of
 freed 2048-byte region [ffff888034836000, ffff888034836800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34830
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 ffff88813ff27000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000d20c01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 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 (syz-executor), ts 87941641236, free_ts 67326119735
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3039 [inline]
 allocate_slab+0x96/0x3a0 mm/slub.c:3212
 new_slab mm/slub.c:3266 [inline]
 ___slab_alloc+0xb12/0x13f0 mm/slub.c:4636
 __slab_alloc+0xc6/0x1f0 mm/slub.c:4755
 __slab_alloc_node mm/slub.c:4831 [inline]
 slab_alloc_node mm/slub.c:5253 [inline]
 __kmalloc_cache_noprof+0xec/0x6c0 mm/slub.c:5743
 kmalloc_noprof include/linux/slab.h:957 [inline]
 rtnl_newlink+0xfb/0x1c80 net/core/rtnetlink.c:3965
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x846/0xa10 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 __sys_sendto+0x3c7/0x520 net/socket.c:2244
 __do_sys_sendto net/socket.c:2251 [inline]
 __se_sys_sendto net/socket.c:2247 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2247
page last free pid 5657 tgid 5657 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xfb6/0x1140 mm/page_alloc.c:2906
 __slab_free+0x2c6/0x370 mm/slub.c:5947
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4955 [inline]
 slab_alloc_node mm/slub.c:5265 [inline]
 __do_kmalloc_node mm/slub.c:5626 [inline]
 __kmalloc_noprof+0x1e1/0x7d0 mm/slub.c:5639
 kmalloc_noprof include/linux/slab.h:961 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x213/0x4b0 security/tomoyo/file.c:822
 security_inode_getattr+0x12f/0x330 security/security.c:2416
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat fs/stat.c:281 [inline]
 __do_sys_newfstat fs/stat.c:555 [inline]
 __se_sys_newfstat fs/stat.c:550 [inline]
 __x64_sys_newfstat+0xfc/0x200 fs/stat.c:550
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888034836680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888034836700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888034836780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff888034836800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888034836880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================