=========================
WARNING: held lock freed!
syzkaller #0 Tainted: G             L     
-------------------------
syz.3.1372/11003 is freeing memory ffff888058b11000-ffff888058b117ff, with a lock still held there!
ffff888058b11260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
ffff888058b11260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0x33a/0x920 net/bluetooth/af_bluetooth.c:312
3 locks held by syz.3.1372/11003:
 #0: ffff88802ed81a40 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
 #0: ffff88802ed81a40 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:721
 #1: ffff888058e81260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP/2){+.+.}-{0:0}, at: l2cap_sock_release+0x61/0x280 net/bluetooth/l2cap_sock.c:1455
 #2: ffff888058b11260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #2: ffff888058b11260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0x33a/0x920 net/bluetooth/af_bluetooth.c:312

stack backtrace:
CPU: 2 UID: 0 PID: 11003 Comm: syz.3.1372 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:2617 [inline]
 slab_free mm/slub.c:6251 [inline]
 kfree+0x178/0x6c0 mm/slub.c:6566
 sk_prot_free net/core/sock.c:2286 [inline]
 __sk_destruct+0x88c/0xab0 net/core/sock.c:2386
 sk_destruct+0xc8/0xf0 net/core/sock.c:2414
 __sk_free+0xf4/0x3e0 net/core/sock.c:2425
 sk_free+0x61/0x90 net/core/sock.c:2436
 sock_put include/net/sock.h:2010 [inline]
 bt_accept_unlink+0x22a/0x370 net/bluetooth/af_bluetooth.c:270
 bt_accept_dequeue+0x791/0x920 net/bluetooth/af_bluetooth.c:339
 l2cap_sock_cleanup_listen+0x30/0x3d0 net/bluetooth/l2cap_sock.c:1503
 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1456
 __sock_release+0xb3/0x260 net/socket.c:722
 sock_close+0x1c/0x30 net/socket.c:1514
 __fput+0x3ff/0xb50 fs/file_table.c:510
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x951/0x2af0 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119
 get_signal+0x20ff/0x2210 kernel/signal.c:3037
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x8b/0x4f0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x706/0x860 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcb7015d68e
Code: Unable to access opcode bytes at 0x7fcb7015d664.
RSP: 002b:00007fcb70fcff58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007fcb70fd06c0 RCX: 00007fcb7015d68e
RDX: 00007fcb70fcffb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fcb70232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb70416038 R14: 00007fcb70415fa0 R15: 00007fff37cf7628
 </TASK>
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:283 [inline]
BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:366 [inline]
BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:383 [inline]
BUG: KASAN: slab-use-after-free in sock_hold include/net/sock.h:839 [inline]
BUG: KASAN: slab-use-after-free in bt_accept_dequeue+0x6bd/0x920 net/bluetooth/af_bluetooth.c:351
Write of size 4 at addr ffff888058b11080 by task syz.3.1372/11003

CPU: 3 UID: 0 PID: 11003 Comm: syz.3.1372 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+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1d0 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:186 [inline]
 kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200
 instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
 atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
 __refcount_add include/linux/refcount.h:283 [inline]
 __refcount_inc include/linux/refcount.h:366 [inline]
 refcount_inc include/linux/refcount.h:383 [inline]
 sock_hold include/net/sock.h:839 [inline]
 bt_accept_dequeue+0x6bd/0x920 net/bluetooth/af_bluetooth.c:351
 l2cap_sock_cleanup_listen+0x30/0x3d0 net/bluetooth/l2cap_sock.c:1503
 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1456
 __sock_release+0xb3/0x260 net/socket.c:722
 sock_close+0x1c/0x30 net/socket.c:1514
 __fput+0x3ff/0xb50 fs/file_table.c:510
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x951/0x2af0 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119
 get_signal+0x20ff/0x2210 kernel/signal.c:3037
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x8b/0x4f0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x706/0x860 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcb7015d68e
Code: Unable to access opcode bytes at 0x7fcb7015d664.
RSP: 002b:00007fcb70fcff58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007fcb70fd06c0 RCX: 00007fcb7015d68e
RDX: 00007fcb70fcffb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fcb70232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb70416038 R14: 00007fcb70415fa0 R15: 00007fff37cf7628
 </TASK>

Allocated by task 5748:
 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:5296 [inline]
 __kmalloc_noprof+0x301/0x850 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2247
 sk_alloc+0x36/0xe80 net/core/sock.c:2303
 bt_sock_alloc+0x3b/0x3c0 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc.constprop.0+0x33/0x1e0 net/bluetooth/l2cap_sock.c:1971
 l2cap_sock_new_connection_cb+0x10f/0x260 net/bluetooth/l2cap_sock.c:1550
 l2cap_connect_cfm+0x4e2/0xf80 net/bluetooth/l2cap_core.c:7402
 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
 hci_remote_features_evt+0x4f4/0x9b0 net/bluetooth/hci_event.c:3760
 hci_event_func net/bluetooth/hci_event.c:7796 [inline]
 hci_event_packet+0x8e9/0xcd0 net/bluetooth/hci_event.c:7847
 hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4077
 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 11003:
 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:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kfree+0x223/0x6c0 mm/slub.c:6566
 sk_prot_free net/core/sock.c:2286 [inline]
 __sk_destruct+0x88c/0xab0 net/core/sock.c:2386
 sk_destruct+0xc8/0xf0 net/core/sock.c:2414
 __sk_free+0xf4/0x3e0 net/core/sock.c:2425
 sk_free+0x61/0x90 net/core/sock.c:2436
 sock_put include/net/sock.h:2010 [inline]
 bt_accept_unlink+0x22a/0x370 net/bluetooth/af_bluetooth.c:270
 bt_accept_dequeue+0x791/0x920 net/bluetooth/af_bluetooth.c:339
 l2cap_sock_cleanup_listen+0x30/0x3d0 net/bluetooth/l2cap_sock.c:1503
 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1456
 __sock_release+0xb3/0x260 net/socket.c:722
 sock_close+0x1c/0x30 net/socket.c:1514
 __fput+0x3ff/0xb50 fs/file_table.c:510
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x951/0x2af0 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119
 get_signal+0x20ff/0x2210 kernel/signal.c:3037
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x8b/0x4f0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x706/0x860 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888058b11000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
 freed 2048-byte region [ffff888058b11000, ffff888058b11800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x58b10
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 ffff88801b842f00 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b842f00 dead000000000100 dead000000000122
head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 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 5130, tgid 5130 (klogd), ts 86741461234, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab mm/slub.c:3467 [inline]
 new_slab+0xa6/0x6c0 mm/slub.c:3525
 refill_objects+0x277/0x420 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5415
 kmalloc_noprof include/linux/slab.h:950 [inline]
 syslog_print+0xf8/0x620 kernel/printk/printk.c:1585
 do_syslog+0x5bd/0x6d0 kernel/printk/printk.c:1763
 __do_sys_syslog kernel/printk/printk.c:1855 [inline]
 __se_sys_syslog kernel/printk/printk.c:1853 [inline]
 __x64_sys_syslog+0x74/0xb0 kernel/printk/printk.c:1853
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x860 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888058b10f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888058b11000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888058b11080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888058b11100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888058b11180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================