syzbot

 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
kobject_add_internal failed for hci3:201 with -EEXIST, don't try to register things with the same name in the same directory.
Bluetooth: hci3: failed to register connection device
==================================================================
BUG: KASAN: use-after-free in l2cap_sock_ready_cb+0xd3/0x140 net/bluetooth/l2cap_sock.c:1665
Read of size 8 at addr ffff88807c8bd4c8 by task kworker/u5:7/4205

CPU: 0 PID: 4205 Comm: kworker/u5:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: hci3 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 l2cap_sock_ready_cb+0xd3/0x140 net/bluetooth/l2cap_sock.c:1665
 l2cap_chan_ready net/bluetooth/l2cap_core.c:1387 [inline]
 l2cap_le_start+0x73b/0x1710 net/bluetooth/l2cap_core.c:1499
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1769 [inline]
 l2cap_connect_cfm+0x6d7/0x10f0 net/bluetooth/l2cap_core.c:8381
 hci_connect_cfm include/net/bluetooth/hci_core.h:1505 [inline]
 le_conn_complete_evt+0xd42/0x15c0 net/bluetooth/hci_event.c:5459
 hci_le_conn_complete_evt net/bluetooth/hci_event.c:5484 [inline]
 hci_le_meta_evt+0x285/0x3c90 net/bluetooth/hci_event.c:6206
 hci_event_packet+0xe48/0x1370 net/bluetooth/hci_event.c:6555
 hci_rx_work+0x255/0xa10 net/bluetooth/hci_core.c:5164
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Allocated by task 4331:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:612 [inline]
 sk_prot_alloc+0xe7/0x210 net/core/sock.c:1866
 sk_alloc+0x2f/0x310 net/core/sock.c:1922
 l2cap_sock_alloc+0x33/0x200 net/bluetooth/l2cap_sock.c:1870
 l2cap_sock_create+0x118/0x1d0 net/bluetooth/l2cap_sock.c:1918
 bt_sock_create+0x155/0x220 net/bluetooth/af_bluetooth.c:130
 __sock_create+0x47b/0x900 net/socket.c:1495
 sock_create net/socket.c:1551 [inline]
 __sys_socket+0xe2/0x170 net/socket.c:1593
 __do_sys_socket net/socket.c:1602 [inline]
 __se_sys_socket net/socket.c:1600 [inline]
 __x64_sys_socket+0x76/0x80 net/socket.c:1600
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 4330:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4564
 sk_prot_free net/core/sock.c:1905 [inline]
 __sk_destruct+0x578/0x840 net/core/sock.c:1991
 l2cap_sock_release+0x169/0x1e0 net/bluetooth/l2cap_sock.c:1432
 __sock_release net/socket.c:651 [inline]
 sock_close+0xd5/0x240 net/socket.c:1345
 __fput+0x234/0x930 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88807c8bd000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1224 bytes inside of
 2048-byte region [ffff88807c8bd000, ffff88807c8bd800)
The buggy address belongs to the page:
page:ffffea0001f22e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7c8b8
head:ffffea0001f22e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888016c42000
raw: 0000000000000000 0000000000080008 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 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 23, ts 75178384349, free_ts 75158848830
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 __kmalloc_node_track_caller+0x1fc/0x3a0 mm/slub.c:4963
 kmalloc_reserve net/core/skbuff.c:356 [inline]
 __alloc_skb+0x22c/0x750 net/core/skbuff.c:427
 skb_copy+0x139/0x790 net/core/skbuff.c:1595
 mac80211_hwsim_tx_frame_no_nl+0xce0/0x1600 drivers/net/wireless/mac80211_hwsim.c:1569
 mac80211_hwsim_tx+0x742/0xe20 drivers/net/wireless/mac80211_hwsim.c:1673
 drv_tx net/mac80211/driver-ops.h:35 [inline]
 ieee80211_tx_frags+0x3f4/0x8d0 net/mac80211/tx.c:1721
 __ieee80211_tx+0x21b/0x4e0 net/mac80211/tx.c:1775
 ieee80211_tx+0x30f/0x460 net/mac80211/tx.c:1955
 __ieee80211_subif_start_xmit+0x1036/0x3290 net/mac80211/tx.c:4257
 ieee80211_subif_start_xmit+0xed/0x5d0 net/mac80211/tx.c:4396
 __netdev_start_xmit include/linux/netdevice.h:5036 [inline]
 netdev_start_xmit include/linux/netdevice.h:5050 [inline]
 xmit_one net/core/dev.c:3662 [inline]
 dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3678
 sch_direct_xmit+0x25a/0x4b0 net/sched/sch_generic.c:345
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 free_slab mm/slub.c:2020 [inline]
 discard_slab mm/slub.c:2026 [inline]
 __unfreeze_partials+0x1a5/0x200 mm/slub.c:2512
 put_cpu_partial+0x12d/0x190 mm/slub.c:2592
 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc+0x100/0x290 mm/slub.c:3238
 getname_flags+0xb5/0x500 fs/namei.c:138
 do_sys_openat2+0xdd/0x4b0 fs/open.c:1249
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_openat fs/open.c:1287 [inline]
 __se_sys_openat fs/open.c:1282 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1282
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88807c8bd380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807c8bd400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807c8bd480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88807c8bd500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807c8bd580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================