syzbot

 </TASK>
kobject: kobject_add_internal failed for hci2:201 with -EEXIST, don't try to register things with the same name in the same directory.
Bluetooth: hci2: failed to register connection device
==================================================================
BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x1f9/0x2a0 net/bluetooth/l2cap_sock.c:1484
Read of size 8 at addr ffff88805e8de548 by task kworker/u5:1/5085

CPU: 0 PID: 5085 Comm: kworker/u5:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: hci2 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 l2cap_sock_new_connection_cb+0x1f9/0x2a0 net/bluetooth/l2cap_sock.c:1484
 l2cap_connect_cfm+0x375/0x1070 net/bluetooth/l2cap_core.c:7259
 hci_connect_cfm+0x8f/0x130 include/net/bluetooth/hci_core.h:1999
 le_conn_complete_evt+0xfdc/0x1540 net/bluetooth/hci_event.c:5786
 hci_le_conn_complete_evt+0x187/0x440 net/bluetooth/hci_event.c:5812
 hci_event_func net/bluetooth/hci_event.c:7454 [inline]
 hci_event_packet+0x7ba/0x1270 net/bluetooth/hci_event.c:7509
 hci_rx_work+0x43a/0xd60 net/bluetooth/hci_core.c:4018
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Allocated by task 5085:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0xb4/0x230 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 sk_prot_alloc+0xe7/0x210 net/core/sock.c:2096
 sk_alloc+0x3a/0x360 net/core/sock.c:2152
 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:148
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1881 [inline]
 l2cap_sock_new_connection_cb+0xe2/0x2a0 net/bluetooth/l2cap_sock.c:1469
 l2cap_connect_cfm+0x375/0x1070 net/bluetooth/l2cap_core.c:7259
 hci_connect_cfm+0x8f/0x130 include/net/bluetooth/hci_core.h:1999
 le_conn_complete_evt+0xfdc/0x1540 net/bluetooth/hci_event.c:5786
 hci_le_conn_complete_evt+0x187/0x440 net/bluetooth/hci_event.c:5812
 hci_event_func net/bluetooth/hci_event.c:7454 [inline]
 hci_event_packet+0x7ba/0x1270 net/bluetooth/hci_event.c:7509
 hci_rx_work+0x43a/0xd60 net/bluetooth/hci_core.c:4018
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Freed by task 6113:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843
 sk_prot_free net/core/sock.c:2135 [inline]
 __sk_destruct+0x4e0/0x660 net/core/sock.c:2230
 l2cap_sock_cleanup_listen+0xda/0x3e0 net/bluetooth/l2cap_sock.c:1449
 l2cap_sock_release+0x6a/0x1e0 net/bluetooth/l2cap_sock.c:1410
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbd/0x230 net/socket.c:1420
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 get_signal+0x1235/0x13f0 kernel/signal.c:2678
 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88805e8de000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1352 bytes inside of
 freed 2048-byte region [ffff88805e8de000, ffff88805e8de800)

The buggy address belongs to the physical page:
page:ffffea00017a3600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5e8d8
head:ffffea00017a3600 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017c42000 dead000000000100 dead000000000122
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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5129, tgid 5129 (klogd), ts 85470510543, free_ts 27931593026
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581
 prep_new_page mm/page_alloc.c:1588 [inline]
 get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4486
 alloc_slab_page+0x5d/0x160 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5d/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x19e/0x250 mm/slub.c:3534
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 syslog_print+0x104/0x630 kernel/printk/printk.c:1553
 do_syslog+0x575/0x820 kernel/printk/printk.c:1732
 __do_sys_syslog kernel/printk/printk.c:1824 [inline]
 __se_sys_syslog kernel/printk/printk.c:1822 [inline]
 __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1822
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1181 [inline]
 free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458
 free_contig_range+0xa1/0x150 mm/page_alloc.c:6406
 destroy_args+0x80/0x850 mm/debug_vm_pgtable.c:1015
 debug_vm_pgtable+0x411/0x440 mm/debug_vm_pgtable.c:1400
 do_one_initcall+0x242/0x790 init/main.c:1250
 do_initcall_level+0x137/0x1f0 init/main.c:1312
 do_initcalls+0x69/0xd0 init/main.c:1328
 kernel_init_freeable+0x3ed/0x580 init/main.c:1565
 kernel_init+0x1d/0x1c0 init/main.c:1455
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Memory state around the buggy address:
 ffff88805e8de400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805e8de480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805e8de500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88805e8de580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805e8de600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================