=========================
WARNING: held lock freed!
syzkaller #0 Tainted: G             L     
-------------------------
syz.1.767/8873 is freeing memory ffff88807cb32000-ffff88807cb327ff, with a lock still held there!
ffff88807cb32260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline]
ffff88807cb32260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0xf3/0x5d0 net/bluetooth/af_bluetooth.c:279
3 locks held by syz.1.767/8873:
 #0: ffff888052868d88 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888052868d88 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: __sock_release+0x89/0x250 net/socket.c:665
 #1: ffff88804b506260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP/2){+.+.}-{0:0}, at: l2cap_sock_release+0x62/0x230 net/bluetooth/l2cap_sock.c:1443
 #2: ffff88807cb32260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1700 [inline]
 #2: ffff88807cb32260 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: bt_accept_dequeue+0xf3/0x5d0 net/bluetooth/af_bluetooth.c:279

stack backtrace:
CPU: 0 UID: 0 PID: 8873 Comm: syz.1.767 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_freed_lock_bug kernel/locking/lockdep.c:6693 [inline]
 debug_check_no_locks_freed+0x149/0x170 kernel/locking/lockdep.c:6728
 slab_free_hook mm/slub.c:2595 [inline]
 slab_free mm/slub.c:6079 [inline]
 kfree+0x127/0x610 mm/slub.c:6392
 sk_prot_free net/core/sock.c:2284 [inline]
 __sk_destruct+0x623/0x880 net/core/sock.c:2384
 bt_accept_dequeue+0x3f6/0x5d0 net/bluetooth/af_bluetooth.c:308
 l2cap_sock_cleanup_listen+0x30/0x440 net/bluetooth/l2cap_sock.c:1472
 l2cap_sock_release+0x6a/0x230 net/bluetooth/l2cap_sock.c:1444
 __sock_release+0xb9/0x250 net/socket.c:666
 sock_close+0x1c/0x30 net/socket.c:1470
 __fput+0x44f/0xa70 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 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_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff53a19aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4eafc3d8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffd4eafc4c0 RCX: 00007ff53a19aeb9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000003aa40 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2fa20000 R11: 0000000000000246 R12: 00007ffd4eafc500
R13: 00007ff53a415fac R14: 000000000003b63a R15: 00007ff53a415fa0
 </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+0x28b/0x2f0 kernel/locking/spinlock_debug.c:115
Read of size 4 at addr ffff88807cb321cc by task syz.1.767/8873

CPU: 1 UID: 0 PID: 8873 Comm: syz.1.767 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
 do_raw_spin_lock+0x28b/0x2f0 kernel/locking/spinlock_debug.c:115
 spin_lock_bh include/linux/spinlock.h:347 [inline]
 release_sock+0x2f/0x1f0 net/core/sock.c:3793
 bt_accept_dequeue+0x555/0x5d0 net/bluetooth/af_bluetooth.c:312
 l2cap_sock_cleanup_listen+0x30/0x440 net/bluetooth/l2cap_sock.c:1472
 l2cap_sock_release+0x6a/0x230 net/bluetooth/l2cap_sock.c:1444
 __sock_release+0xb9/0x250 net/socket.c:666
 sock_close+0x1c/0x30 net/socket.c:1470
 __fput+0x44f/0xa70 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 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_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff53a19aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4eafc3d8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffd4eafc4c0 RCX: 00007ff53a19aeb9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000003aa40 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2fa20000 R11: 0000000000000246 R12: 00007ffd4eafc500
R13: 00007ff53a415fac R14: 000000000003b63a R15: 00007ff53a415fa0
 </TASK>

Allocated by task 5835:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5174 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5186
 kmalloc_noprof include/linux/slab.h:966 [inline]
 sk_prot_alloc+0xe7/0x210 net/core/sock.c:2245
 sk_alloc+0x3a/0x390 net/core/sock.c:2301
 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1915 [inline]
 l2cap_sock_new_connection_cb+0xe2/0x2e0 net/bluetooth/l2cap_sock.c:1503
 l2cap_connect_cfm+0x368/0x1390 net/bluetooth/l2cap_core.c:7306
 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
 hci_remote_features_evt+0x5b9/0x950 net/bluetooth/hci_event.c:3754
 hci_event_func net/bluetooth/hci_event.c:7784 [inline]
 hci_event_packet+0x805/0x12c0 net/bluetooth/hci_event.c:7838
 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077
 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0xb46/0x1140 kernel/workqueue.c:3443
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 8873:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2667 [inline]
 slab_free mm/slub.c:6079 [inline]
 kfree+0x1c1/0x610 mm/slub.c:6392
 sk_prot_free net/core/sock.c:2284 [inline]
 __sk_destruct+0x623/0x880 net/core/sock.c:2384
 bt_accept_dequeue+0x3f6/0x5d0 net/bluetooth/af_bluetooth.c:308
 l2cap_sock_cleanup_listen+0x30/0x440 net/bluetooth/l2cap_sock.c:1472
 l2cap_sock_release+0x6a/0x230 net/bluetooth/l2cap_sock.c:1444
 __sock_release+0xb9/0x250 net/socket.c:666
 sock_close+0x1c/0x30 net/socket.c:1470
 __fput+0x44f/0xa70 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 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_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807cb32000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 460 bytes inside of
 freed 2048-byte region [ffff88807cb32000, ffff88807cb32800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7cb30
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 ffff88813ff27000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ff27000 dead000000000100 dead000000000122
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001f2cc01 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 5821, tgid 5821 (syz-executor), ts 68792622597, free_ts 65712540076
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1883
 prep_new_page mm/page_alloc.c:1891 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3956
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5244
 alloc_slab_page mm/slub.c:3235 [inline]
 allocate_slab+0x7b/0x660 mm/slub.c:3408
 new_slab mm/slub.c:3466 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7084
 refill_sheaf mm/slub.c:2784 [inline]
 __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4533
 alloc_from_pcs mm/slub.c:4636 [inline]
 slab_alloc_node mm/slub.c:4770 [inline]
 __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5289
 kmalloc_noprof include/linux/slab.h:962 [inline]
 rtnl_newlink+0x136/0x1be0 net/core/rtnetlink.c:3972
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
 __sock_sendmsg net/socket.c:752 [inline]
 __sys_sendto+0x3ff/0x590 net/socket.c:2221
 __do_sys_sendto net/socket.c:2228 [inline]
 __se_sys_sendto net/socket.c:2224 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2224
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 5810 tgid 5810 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1432 [inline]
 __free_frozen_pages+0xc01/0xd80 mm/page_alloc.c:2972
 __folio_put+0x414/0x4f0 mm/swap.c:112
 put_netmem include/net/netmem.h:420 [inline]
 skb_page_unref include/linux/skbuff_ref.h:43 [inline]
 __skb_frag_unref include/linux/skbuff_ref.h:56 [inline]
 skb_release_data+0x4cb/0x940 net/core/skbuff.c:1121
 skb_release_all net/core/skbuff.c:1202 [inline]
 __kfree_skb+0x5d/0x210 net/core/skbuff.c:1216
 tcp_clean_rtx_queue net/ipv4/tcp_input.c:3680 [inline]
 tcp_ack+0x2826/0x7da0 net/ipv4/tcp_input.c:4348
 tcp_rcv_established+0x13e6/0x25b0 net/ipv4/tcp_input.c:6603
 tcp_v4_do_rcv+0xa90/0x1430 net/ipv4/tcp_ipv4.c:1881
 sk_backlog_rcv include/net/sock.h:1177 [inline]
 __release_sock+0x265/0x3a0 net/core/sock.c:3213
 __sk_flush_backlog+0x36/0xc0 net/core/sock.c:3236
 sk_flush_backlog include/net/sock.h:1240 [inline]
 tcp_sendmsg_locked+0x4232/0x5430 net/ipv4/tcp.c:1274
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1473
 sock_sendmsg_nosec+0x128/0x1d0 net/socket.c:737
 __sock_sendmsg net/socket.c:752 [inline]
 sock_write_iter+0x302/0x410 net/socket.c:1210
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61d/0xb90 fs/read_write.c:688
 ksys_write+0x150/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff88807cb32080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807cb32100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807cb32180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88807cb32200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807cb32280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================