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BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x1f9/0x2e0 net/bluetooth/l2cap_sock.c:1525
Read of size 8 at addr ffff88802b6ce7b0 by task kworker/u9:3/5804

CPU: 1 UID: 0 PID: 5804 Comm: kworker/u9:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: hci5 hci_rx_work
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
 l2cap_sock_new_connection_cb+0x1f9/0x2e0 net/bluetooth/l2cap_sock.c:1525
 l2cap_connect_cfm+0x368/0x1390 net/bluetooth/l2cap_core.c:7351
 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139
 le_conn_complete_evt+0xf65/0x1430 net/bluetooth/hci_event.c:5847
 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5873
 hci_event_func net/bluetooth/hci_event.c:7781 [inline]
 hci_event_packet+0x7af/0x12c0 net/bluetooth/hci_event.c:7838
 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5804:
 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:5260 [inline]
 __kmalloc_noprof+0x3e7/0x7b0 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [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:1922 [inline]
 l2cap_sock_new_connection_cb+0xe2/0x2e0 net/bluetooth/l2cap_sock.c:1510
 l2cap_connect_cfm+0x368/0x1390 net/bluetooth/l2cap_core.c:7351
 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139
 le_conn_complete_evt+0xf65/0x1430 net/bluetooth/hci_event.c:5847
 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5873
 hci_event_func net/bluetooth/hci_event.c:7781 [inline]
 hci_event_packet+0x7af/0x12c0 net/bluetooth/hci_event.c:7838
 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 15098:
 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:2685 [inline]
 slab_free mm/slub.c:6165 [inline]
 kfree+0x1c1/0x6c0 mm/slub.c:6483
 sk_prot_free net/core/sock.c:2284 [inline]
 __sk_destruct+0x626/0x880 net/core/sock.c:2384
 l2cap_sock_cleanup_listen+0xe0/0x440 net/bluetooth/l2cap_sock.c:1490
 l2cap_sock_release+0x6e/0x270 net/bluetooth/l2cap_sock.c:1451
 __sock_release net/socket.c:662 [inline]
 sock_close+0xc3/0x240 net/socket.c:1455
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 get_signal+0x11c3/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 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 include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802b6ce000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1968 bytes inside of
 freed 2048-byte region [ffff88802b6ce000, ffff88802b6ce800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b6c8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe1d000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe1d000 dead000000000100 dead000000000122
head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000adb201 00000000ffffffff 00000000ffffffff
head: 0000000000000000 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 1019, tgid 1019 (kworker/u8:8), ts 15836036095, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x35c/0x710 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_noprof+0x530/0x7b0 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 scsi_alloc_target+0x138/0xbd0 drivers/scsi/scsi_scan.c:505
 __scsi_scan_target+0x164/0xe10 drivers/scsi/scsi_scan.c:1769
 scsi_scan_channel drivers/scsi/scsi_scan.c:1874 [inline]
 scsi_scan_host_selected+0x375/0x690 drivers/scsi/scsi_scan.c:1903
 do_scsi_scan_host drivers/scsi/scsi_scan.c:2042 [inline]
 do_scan_async+0x124/0x760 drivers/scsi/scsi_scan.c:2052
 async_run_entry_fn+0xa8/0x440 kernel/async.c:129
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802b6ce680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b6ce700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802b6ce780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88802b6ce800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b6ce880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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