=========================
WARNING: held lock freed!
syzkaller #0 Tainted: G             L     
-------------------------
syz.1.4656/23628 is freeing memory ffff88805843b000-ffff88805843b7ff, with a lock still held there!
ffff88805843b260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
ffff88805843b260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0x244/0x690 net/bluetooth/af_bluetooth.c:279
3 locks held by syz.1.4656/23628:
 #0: ffff88805659ccc8 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff88805659ccc8 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:661
 #1: ffff888057507260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP/2){+.+.}-{0:0}, at: l2cap_sock_release+0x61/0x280 net/bluetooth/l2cap_sock.c:1450
 #2: ffff88805843b260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
 #2: ffff88805843b260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0x244/0x690 net/bluetooth/af_bluetooth.c:279

stack backtrace:
CPU: 0 UID: 0 PID: 23628 Comm: syz.1.4656 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_freed_lock_bug kernel/locking/lockdep.c:6693 [inline]
 debug_check_no_locks_freed+0x115/0x120 kernel/locking/lockdep.c:6728
 slab_free_hook mm/slub.c:2613 [inline]
 slab_free mm/slub.c:6165 [inline]
 kfree+0x18b/0x6b0 mm/slub.c:6483
 sk_prot_free net/core/sock.c:2284 [inline]
 __sk_destruct+0x8ab/0xbb0 net/core/sock.c:2384
 sk_destruct+0xc8/0xf0 net/core/sock.c:2412
 __sk_free+0xf4/0x3e0 net/core/sock.c:2423
 sk_free+0x61/0x90 net/core/sock.c:2434
 sock_put include/net/sock.h:2007 [inline]
 bt_accept_unlink+0x1e4/0x2f0 net/bluetooth/af_bluetooth.c:262
 bt_accept_dequeue+0x576/0x690 net/bluetooth/af_bluetooth.c:308
 l2cap_sock_cleanup_listen+0x5c/0x2d0 net/bluetooth/l2cap_sock.c:1479
 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1451
 __sock_release+0xb3/0x260 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 ret_from_fork+0x95b/0xd80 arch/x86/kernel/process.c:167
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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+0x23b/0x260 kernel/locking/spinlock_debug.c:115
Read of size 4 at addr ffff88805843b1cc by task syz.1.4656/23628

CPU: 1 UID: 0 PID: 23628 Comm: syz.1.4656 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
 debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
 do_raw_spin_lock+0x23b/0x260 kernel/locking/spinlock_debug.c:115
 spin_lock_bh include/linux/spinlock.h:347 [inline]
 release_sock+0x21/0x220 net/core/sock.c:3793
 bt_accept_dequeue+0x564/0x690 net/bluetooth/af_bluetooth.c:312
 l2cap_sock_cleanup_listen+0x5c/0x2d0 net/bluetooth/l2cap_sock.c:1479
 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1451
 __sock_release+0xb3/0x260 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 ret_from_fork+0x95b/0xd80 arch/x86/kernel/process.c:167
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5948:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5260 [inline]
 __kmalloc_noprof+0x301/0x850 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2245
 sk_alloc+0x36/0xe80 net/core/sock.c:2301
 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc.constprop.0+0x33/0x1e0 net/bluetooth/l2cap_sock.c:1922
 l2cap_sock_new_connection_cb+0x101/0x260 net/bluetooth/l2cap_sock.c:1510
 l2cap_connect_cfm+0x4e2/0x1050 net/bluetooth/l2cap_core.c:7351
 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
 hci_remote_features_evt+0x4f4/0x9b0 net/bluetooth/hci_event.c:3754
 hci_event_func net/bluetooth/hci_event.c:7784 [inline]
 hci_event_packet+0xa86/0x11c0 net/bluetooth/hci_event.c:7838
 hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4077
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 23628:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2685 [inline]
 slab_free mm/slub.c:6165 [inline]
 kfree+0x1f6/0x6b0 mm/slub.c:6483
 sk_prot_free net/core/sock.c:2284 [inline]
 __sk_destruct+0x8ab/0xbb0 net/core/sock.c:2384
 sk_destruct+0xc8/0xf0 net/core/sock.c:2412
 __sk_free+0xf4/0x3e0 net/core/sock.c:2423
 sk_free+0x61/0x90 net/core/sock.c:2434
 sock_put include/net/sock.h:2007 [inline]
 bt_accept_unlink+0x1e4/0x2f0 net/bluetooth/af_bluetooth.c:262
 bt_accept_dequeue+0x576/0x690 net/bluetooth/af_bluetooth.c:308
 l2cap_sock_cleanup_listen+0x5c/0x2d0 net/bluetooth/l2cap_sock.c:1479
 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1451
 __sock_release+0xb3/0x260 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 ret_from_fork+0x95b/0xd80 arch/x86/kernel/process.c:167
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88805843b000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 460 bytes inside of
 freed 2048-byte region [ffff88805843b000, ffff88805843b800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88805843e000 pfn:0x58438
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 ffff88801b842f00 ffffea0001588e10 ffffea00009b8a10
raw: ffff88805843e000 0000000800080003 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801b842f00 ffffea0001588e10 ffffea00009b8a10
head: ffff88805843e000 0000000800080003 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001610e01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 14935, tgid 14935 (kworker/0:7), ts 550501619867, free_ts 546834676043
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab mm/slub.c:3481 [inline]
 new_slab+0xa6/0x6b0 mm/slub.c:3539
 refill_objects+0x26b/0x400 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x1ab/0x660 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kmalloc_node_track_caller_noprof+0x694/0x850 mm/slub.c:5368
 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:635
 __alloc_skb+0x185/0x710 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1383 [inline]
 mld_newpack.isra.0+0x18e/0xa20 net/ipv6/mcast.c:1775
 add_grhead+0x299/0x340 net/ipv6/mcast.c:1886
 add_grec+0x1380/0x1920 net/ipv6/mcast.c:2025
 mld_send_initial_cr+0x156/0x320 net/ipv6/mcast.c:2268
 mld_dad_work+0x32/0x1f0 net/ipv6/mcast.c:2294
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
page last free pid 17175 tgid 17175 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_lru_noprof+0x246/0x6e0 mm/slub.c:4885
 sock_alloc_inode+0x25/0x1c0 net/socket.c:322
 alloc_inode+0x68/0x250 fs/inode.c:347
 new_inode_pseudo include/linux/fs.h:3003 [inline]
 sock_alloc+0x44/0x280 net/socket.c:637
 __sock_create+0xc2/0x860 net/socket.c:1569
 sock_create net/socket.c:1663 [inline]
 __sys_socket_create net/socket.c:1700 [inline]
 __sys_socket+0x14d/0x260 net/socket.c:1747
 __do_sys_socket net/socket.c:1761 [inline]
 __se_sys_socket net/socket.c:1759 [inline]
 __x64_sys_socket+0x72/0xb0 net/socket.c:1759
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88805843b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805843b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805843b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88805843b200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805843b280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================