bridge0: port 3(syz_tun) entered disabled state
syz_tun (unregistering): left allmulticast mode
bridge0: port 3(syz_tun) entered disabled state
=========================
WARNING: held lock freed!
syzkaller #0 Not tainted
-------------------------
syz.4.1976/15340 is freeing memory ffff888028215000-ffff8880282157ff, with a lock still held there!
ffff888028215258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
ffff888028215258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0x249/0x670 net/bluetooth/af_bluetooth.c:279
3 locks held by syz.4.1976/15340:
 #0: ffff888056870d88 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
 #0: ffff888056870d88 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:661
 #1: ffff8880358a3258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP/2){+.+.}-{0:0}, at: l2cap_sock_release+0x61/0x250 net/bluetooth/l2cap_sock.c:1425
 #2: ffff888028215258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
 #2: ffff888028215258 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0x249/0x670 net/bluetooth/af_bluetooth.c:279

stack backtrace:
CPU: 0 UID: 0 PID: 15340 Comm: syz.4.1976 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_freed_lock_bug kernel/locking/lockdep.c:6693 [inline]
 debug_check_no_locks_freed+0x134/0x170 kernel/locking/lockdep.c:6728
 slab_free_hook mm/slub.c:2451 [inline]
 slab_free mm/slub.c:6611 [inline]
 kfree+0xe0/0x6d0 mm/slub.c:6818
 sk_prot_free net/core/sock.c:2278 [inline]
 __sk_destruct+0x75f/0x9a0 net/core/sock.c:2373
 sk_destruct+0xc2/0xf0 net/core/sock.c:2401
 __sk_free+0xf4/0x3e0 net/core/sock.c:2412
 sk_free+0x6a/0x90 net/core/sock.c:2423
 sock_put include/net/sock.h:1972 [inline]
 bt_accept_unlink+0x23c/0x2d0 net/bluetooth/af_bluetooth.c:262
 bt_accept_dequeue+0x569/0x670 net/bluetooth/af_bluetooth.c:308
 l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1454
 l2cap_sock_release+0x69/0x250 net/bluetooth/l2cap_sock.c:1426
 __sock_release+0xb3/0x270 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x402/0xb70 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x86f/0x2bf0 kernel/exit.c:966
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
 get_signal+0x2671/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x85/0x130 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+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0f359c1885
Code: Unable to access opcode bytes at 0x7f0f359c185b.
RSP: 002b:00007f0f367c8f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f0f35be6090 RCX: 00007f0f359c1885
RDX: 00007f0f367c8fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f0f35a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f0f35be6128 R14: 00007f0f35be6090 R15: 00007ffde16ce6f8
 </TASK>
==================================================================
BUG: KASAN: slab-use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
BUG: KASAN: slab-use-after-free in do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115
Read of size 4 at addr ffff8880282151c4 by task syz.4.1976/15340

CPU: 0 UID: 0 PID: 15340 Comm: syz.4.1976 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
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:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
 do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 release_sock+0x21/0x220 net/core/sock.c:3733
 bt_accept_dequeue+0x557/0x670 net/bluetooth/af_bluetooth.c:312
 l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1454
 l2cap_sock_release+0x69/0x250 net/bluetooth/l2cap_sock.c:1426
 __sock_release+0xb3/0x270 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x402/0xb70 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x86f/0x2bf0 kernel/exit.c:966
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
 get_signal+0x2671/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x85/0x130 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+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0f359c1885
Code: Unable to access opcode bytes at 0x7f0f359c185b.
RSP: 002b:00007f0f367c8f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f0f35be6090 RCX: 00007f0f359c1885
RDX: 00007f0f367c8fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f0f35a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f0f35be6128 R14: 00007f0f35be6090 R15: 00007ffde16ce6f8
 </TASK>

Allocated by task 5944:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5627 [inline]
 __kmalloc_noprof+0x32f/0x880 mm/slub.c:5639
 kmalloc_noprof include/linux/slab.h:961 [inline]
 sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2239
 sk_alloc+0x36/0xc20 net/core/sock.c:2295
 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc.constprop.0+0x33/0x1d0 net/bluetooth/l2cap_sock.c:1897
 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1485
 l2cap_connect_cfm+0x4c7/0xf80 net/bluetooth/l2cap_core.c:7287
 hci_connect_cfm include/net/bluetooth/hci_core.h:2106 [inline]
 hci_remote_features_evt+0x4e0/0x970 net/bluetooth/hci_event.c:3728
 hci_event_func net/bluetooth/hci_event.c:7559 [inline]
 hci_event_packet+0xa10/0x11c0 net/bluetooth/hci_event.c:7613
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4099
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 15340:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 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+0x5f/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+0x2b8/0x6d0 mm/slub.c:6818
 sk_prot_free net/core/sock.c:2278 [inline]
 __sk_destruct+0x75f/0x9a0 net/core/sock.c:2373
 sk_destruct+0xc2/0xf0 net/core/sock.c:2401
 __sk_free+0xf4/0x3e0 net/core/sock.c:2412
 sk_free+0x6a/0x90 net/core/sock.c:2423
 sock_put include/net/sock.h:1972 [inline]
 bt_accept_unlink+0x23c/0x2d0 net/bluetooth/af_bluetooth.c:262
 bt_accept_dequeue+0x569/0x670 net/bluetooth/af_bluetooth.c:308
 l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1454
 l2cap_sock_release+0x69/0x250 net/bluetooth/l2cap_sock.c:1426
 __sock_release+0xb3/0x270 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x402/0xb70 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x86f/0x2bf0 kernel/exit.c:966
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
 get_signal+0x2671/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x85/0x130 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+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888028215000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 452 bytes inside of
 freed 2048-byte region [ffff888028215000, ffff888028215800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888028217000 pfn:0x28210
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801b442f00 ffffea000092ce10 ffffea0000cada10
raw: ffff888028217000 0000000000080006 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801b442f00 ffffea000092ce10 ffffea0000cada10
head: ffff888028217000 0000000000080006 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000a08401 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 5936, tgid 5936 (syz-executor), ts 65711305083, free_ts 65668028696
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3039 [inline]
 allocate_slab mm/slub.c:3212 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3266
 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4636
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4755
 __slab_alloc_node mm/slub.c:4831 [inline]
 slab_alloc_node mm/slub.c:5253 [inline]
 __do_kmalloc_node mm/slub.c:5626 [inline]
 __kmalloc_node_track_caller_noprof+0x4db/0x8a0 mm/slub.c:5736
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:601
 pskb_expand_head+0x238/0x1030 net/core/skbuff.c:2241
 netlink_trim+0x22d/0x310 net/netlink/af_netlink.c:1301
 netlink_broadcast_filtered+0xf1/0xf90 net/netlink/af_netlink.c:1514
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0x9e/0x220 net/netlink/af_netlink.c:2595
 rtnl_notify net/core/rtnetlink.c:958 [inline]
 rtmsg_ifinfo_send net/core/rtnetlink.c:4429 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4445 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4432 [inline]
 rtmsg_ifinfo+0x174/0x1a0 net/core/rtnetlink.c:4451
 __dev_notify_flags+0x24c/0x2e0 net/core/dev.c:9672
 rtnl_configure_link+0x1b5/0x280 net/core/rtnetlink.c:3599
page last free pid 5936 tgid 5936 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906
 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: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]
 __kmalloc_cache_noprof+0x274/0x780 mm/slub.c:5743
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 ref_tracker_alloc+0x18e/0x5b0 lib/ref_tracker.c:271
 __netdev_tracker_alloc include/linux/netdevice.h:4375 [inline]
 netdev_hold include/linux/netdevice.h:4404 [inline]
 netdev_hold include/linux/netdevice.h:4399 [inline]
 netdev_queue_add_kobject net/core/net-sysfs.c:1994 [inline]
 netdev_queue_update_kobjects+0x2db/0x720 net/core/net-sysfs.c:2056
 register_queue_kobjects net/core/net-sysfs.c:2119 [inline]
 netdev_register_kobject+0x2b3/0x3d0 net/core/net-sysfs.c:2362
 register_netdevice+0x13dc/0x2270 net/core/dev.c:11294
 veth_newlink+0x44d/0xa00 drivers/net/veth.c:1884
 rtnl_newlink_create net/core/rtnetlink.c:3833 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3950 [inline]
 rtnl_newlink+0xc45/0x2000 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6954
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 __sys_sendto+0x4a3/0x520 net/socket.c:2244

Memory state around the buggy address:
 ffff888028215080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028215100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028215180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888028215200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028215280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================