syzbot

 </TASK>
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_sock_ready_cb+0xce/0x130 net/bluetooth/l2cap_sock.c:1704
Read of size 8 at addr ffff8880555254a8 by task kworker/u5:4/4261

CPU: 0 PID: 4261 Comm: kworker/u5:4 Not tainted 6.1.119-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 l2cap_sock_ready_cb+0xce/0x130 net/bluetooth/l2cap_sock.c:1704
 l2cap_chan_ready net/bluetooth/l2cap_core.c:1409 [inline]
 l2cap_le_start+0x4d2/0x17b0 net/bluetooth/l2cap_core.c:1521
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1790 [inline]
 l2cap_connect_cfm+0x72b/0x1270 net/bluetooth/l2cap_core.c:8334
 hci_connect_cfm+0x9e/0x150 include/net/bluetooth/hci_core.h:1787
 le_conn_complete_evt+0xd54/0x1320 net/bluetooth/hci_event.c:5864
 hci_le_conn_complete_evt+0x188/0x410 net/bluetooth/hci_event.c:5890
 hci_event_func net/bluetooth/hci_event.c:7370 [inline]
 hci_event_packet+0xa40/0x1510 net/bluetooth/hci_event.c:7425
 hci_rx_work+0x3cd/0xce0 net/bluetooth/hci_core.c:4085
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Allocated by task 4484:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x97/0xb0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:936 [inline]
 __kmalloc+0xb2/0x230 mm/slab_common.c:949
 kmalloc include/linux/slab.h:562 [inline]
 sk_prot_alloc+0xe0/0x200 net/core/sock.c:2047
 sk_alloc+0x36/0x350 net/core/sock.c:2100
 bt_sock_alloc+0x37/0x130 net/bluetooth/af_bluetooth.c:148
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1911 [inline]
 l2cap_sock_create+0x11e/0x2b0 net/bluetooth/l2cap_sock.c:1951
 bt_sock_create+0x159/0x220 net/bluetooth/af_bluetooth.c:132
 __sock_create+0x488/0x930 net/socket.c:1550
 sock_create net/socket.c:1606 [inline]
 __sys_socket_create net/socket.c:1643 [inline]
 __sys_socket+0x136/0x3a0 net/socket.c:1671
 __do_sys_socket net/socket.c:1684 [inline]
 __se_sys_socket net/socket.c:1682 [inline]
 __x64_sys_socket+0x76/0x80 net/socket.c:1682
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 4490:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1724 [inline]
 slab_free_freelist_hook mm/slub.c:1750 [inline]
 slab_free mm/slub.c:3661 [inline]
 __kmem_cache_free+0x25c/0x3c0 mm/slub.c:3674
 sk_prot_free net/core/sock.c:2083 [inline]
 __sk_destruct+0x473/0x5f0 net/core/sock.c:2169
 l2cap_sock_release+0x157/0x1d0 net/bluetooth/l2cap_sock.c:1455
 __sock_release net/socket.c:654 [inline]
 sock_close+0xcd/0x230 net/socket.c:1400
 __fput+0x3f6/0x8d0 fs/file_table.c:320
 task_work_run+0x246/0x300 kernel/task_work.c:203
 get_signal+0x15fc/0x17d0 kernel/signal.c:2648
 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888055525000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1192 bytes inside of
 2048-byte region [ffff888055525000, ffff888055525800)

The buggy address belongs to the physical page:
page:ffffea0001554800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x55520
head:ffffea0001554800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0000a79200 dead000000000002 ffff888017c42000
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 0xd2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11, tgid 11 (kworker/u4:1), ts 78175467642, free_ts 20804585807
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2517
 prep_new_page mm/page_alloc.c:2524 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4313
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5590
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc_node_track_caller+0xa0/0x220 mm/slab_common.c:956
 kmalloc_reserve net/core/skbuff.c:446 [inline]
 __alloc_skb+0x135/0x670 net/core/skbuff.c:515
 alloc_skb include/linux/skbuff.h:1271 [inline]
 nlmsg_new include/net/netlink.h:991 [inline]
 inet6_ifinfo_notify+0x69/0x110 net/ipv6/addrconf.c:6081
 addrconf_notify+0xc56/0xf60 net/ipv6/addrconf.c:3689
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:455
 call_netdevice_notifiers_info net/core/dev.c:1970 [inline]
 netdev_state_change+0x1a3/0x250 net/core/dev.c:1359
 linkwatch_do_dev+0x10c/0x160 net/core/link_watch.c:168
 __linkwatch_run_queue+0x448/0x6b0 net/core/link_watch.c:221
 linkwatch_event+0x48/0x50 net/core/link_watch.c:264
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1444 [inline]
 free_pcp_prepare mm/page_alloc.c:1494 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3369
 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3464
 free_contig_range+0x9a/0x150 mm/page_alloc.c:9550
 destroy_args+0xfe/0x997 mm/debug_vm_pgtable.c:1031
 debug_vm_pgtable+0x416/0x46b mm/debug_vm_pgtable.c:1354
 do_one_initcall+0x265/0x8f0 init/main.c:1298
 do_initcall_level+0x157/0x207 init/main.c:1371
 do_initcalls+0x49/0x86 init/main.c:1387
 kernel_init_freeable+0x45c/0x60f init/main.c:1626
 kernel_init+0x19/0x290 init/main.c:1514
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff888055525380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888055525400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888055525480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888055525500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888055525580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================