syzbot

 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
kobject: 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: slab-use-after-free in l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1497
Read of size 8 at addr ffff8880286fd588 by task kworker/u9:6/5832

CPU: 1 UID: 0 PID: 5832 Comm: kworker/u9:6 Not tainted 6.16.0-rc2-syzkaller-00087-g24770983ccfe #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci3 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xcd/0x680 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1497
 l2cap_connect_cfm+0x4c4/0xf80 net/bluetooth/l2cap_core.c:7264
 hci_connect_cfm include/net/bluetooth/hci_core.h:2054 [inline]
 le_conn_complete_evt+0x1665/0x1d70 net/bluetooth/hci_event.c:5791
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5817
 hci_le_meta_evt+0x354/0x5e0 net/bluetooth/hci_event.c:7200
 hci_event_func net/bluetooth/hci_event.c:7508 [inline]
 hci_event_packet+0x685/0x11c0 net/bluetooth/hci_event.c:7565
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4044
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5832:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4328 [inline]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2247
 sk_alloc+0x36/0xc20 net/core/sock.c:2303
 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc.constprop.0+0x33/0x1d0 net/bluetooth/l2cap_sock.c:1891
 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1482
 l2cap_connect_cfm+0x4c4/0xf80 net/bluetooth/l2cap_core.c:7264
 hci_connect_cfm include/net/bluetooth/hci_core.h:2054 [inline]
 le_conn_complete_evt+0x1665/0x1d70 net/bluetooth/hci_event.c:5791
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5817
 hci_le_meta_evt+0x354/0x5e0 net/bluetooth/hci_event.c:7200
 hci_event_func net/bluetooth/hci_event.c:7508 [inline]
 hci_event_packet+0x685/0x11c0 net/bluetooth/hci_event.c:7565
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4044
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 6417:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 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+0x2b4/0x4d0 mm/slub.c:4842
 sk_prot_free net/core/sock.c:2286 [inline]
 __sk_destruct+0x740/0x980 net/core/sock.c:2381
 sk_destruct+0xc2/0xf0 net/core/sock.c:2409
 __sk_free+0xf4/0x3e0 net/core/sock.c:2420
 sk_free+0x6a/0x90 net/core/sock.c:2431
 sock_put include/net/sock.h:1960 [inline]
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1265 [inline]
 l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1250
 l2cap_sock_cleanup_listen+0x3d/0x2a0 net/bluetooth/l2cap_sock.c:1462
 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1425
 __sock_release+0xb0/0x270 net/socket.c:647
 sock_close+0x1c/0x30 net/socket.c:1391
 __fput+0x3ff/0xb70 fs/file_table.c:465
 task_work_run+0x150/0x240 kernel/task_work.c:227
 get_signal+0x1d1/0x26d0 kernel/signal.c:2807
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880286fd000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1416 bytes inside of
 freed 2048-byte region [ffff8880286fd000, ffff8880286fd800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x286f8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b842000 ffffea0001f2ee00 0000000000000002
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b842000 ffffea0001f2ee00 0000000000000002
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000a1be01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6010, tgid 6009 (syz.0.17), ts 74249395106, free_ts 66644952363
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab mm/slub.c:2619 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2673
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4347
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:601
 __alloc_skb+0x166/0x380 net/core/skbuff.c:670
 alloc_skb include/linux/skbuff.h:1336 [inline]
 nlmsg_new include/net/netlink.h:1041 [inline]
 audit_buffer_alloc kernel/audit.c:1795 [inline]
 audit_log_start+0x2ea/0x7f0 kernel/audit.c:1913
 common_lsm_audit+0xb2/0x300 security/lsm_audit.c:442
 slow_avc_audit+0x186/0x210 security/selinux/avc.c:779
 audit_inode_permission+0x1ec/0x2b0 security/selinux/hooks.c:3098
 selinux_inode_permission+0xbd3/0xe80 security/selinux/hooks.c:3239
 security_inode_permission+0xda/0x260 security/security.c:2324
page last free pid 5816 tgid 5816 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x16d/0x1c0 mm/slub.c:3186
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_node_noprof+0x1d5/0x3b0 mm/slub.c:4249
 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1336 [inline]
 nlmsg_new include/net/netlink.h:1041 [inline]
 rtmsg_ifa+0x16a/0x2a0 net/ipv4/devinet.c:2015
 __inet_insert_ifa+0x911/0xcd0 net/ipv4/devinet.c:566
 inet_rtm_newaddr+0xd87/0x1540 net/ipv4/devinet.c:1002
 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg net/socket.c:727 [inline]
 __sys_sendto+0x4a0/0x520 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2183

Memory state around the buggy address:
 ffff8880286fd480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880286fd500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880286fd580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8880286fd600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880286fd680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================