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BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x1f9/0x2b0 net/bluetooth/l2cap_sock.c:1500
Read of size 8 at addr ffff888027bd1798 by task kworker/u9:0/11445

CPU: 0 UID: 0 PID: 11445 Comm: kworker/u9:0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 l2cap_sock_new_connection_cb+0x1f9/0x2b0 net/bluetooth/l2cap_sock.c:1500
 l2cap_connect_cfm+0x377/0x1040 net/bluetooth/l2cap_core.c:7287
 hci_connect_cfm+0x92/0x140 include/net/bluetooth/hci_core.h:2082
 le_conn_complete_evt+0xcd3/0x1220 net/bluetooth/hci_event.c:5771
 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5797
 hci_event_func net/bluetooth/hci_event.c:7542 [inline]
 hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7599
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4071
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 11445:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4376 [inline]
 __kmalloc_noprof+0x1ef/0x430 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 sk_prot_alloc+0xe7/0x220 net/core/sock.c:2239
 sk_alloc+0x3a/0x370 net/core/sock.c:2295
 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1897 [inline]
 l2cap_sock_new_connection_cb+0xe2/0x2b0 net/bluetooth/l2cap_sock.c:1485
 l2cap_connect_cfm+0x377/0x1040 net/bluetooth/l2cap_core.c:7287
 hci_connect_cfm+0x92/0x140 include/net/bluetooth/hci_core.h:2082
 le_conn_complete_evt+0xcd3/0x1220 net/bluetooth/hci_event.c:5771
 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5797
 hci_event_func net/bluetooth/hci_event.c:7542 [inline]
 hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7599
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4071
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 11680:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kfree+0x195/0x550 mm/slub.c:4894
 sk_prot_free net/core/sock.c:2278 [inline]
 __sk_destruct+0x4e4/0x670 net/core/sock.c:2373
 l2cap_sock_cleanup_listen+0xda/0x3e0 net/bluetooth/l2cap_sock.c:1465
 l2cap_sock_release+0x6a/0x230 net/bluetooth/l2cap_sock.c:1426
 __sock_release net/socket.c:649 [inline]
 sock_close+0xc3/0x240 net/socket.c:1439
 __fput+0x45b/0xa80 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43
 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+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888027bd1000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1944 bytes inside of
 freed 2048-byte region [ffff888027bd1000, ffff888027bd1800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27bd0
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 ffff888019842000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 0080000000000040 ffff888019842000 dead000000000100 dead000000000122
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea00009ef401 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 43, tgid 43 (kworker/u8:2), ts 10373785621, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2660
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0x8d1/0xdc0 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 __do_kmalloc_node mm/slub.c:4375 [inline]
 __kmalloc_noprof+0x145/0x430 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 scsi_alloc_target+0x138/0xbb0 drivers/scsi/scsi_scan.c:505
 __scsi_scan_target+0x15b/0xd10 drivers/scsi/scsi_scan.c:1759
 scsi_scan_channel drivers/scsi/scsi_scan.c:1864 [inline]
 scsi_scan_host_selected+0x375/0x690 drivers/scsi/scsi_scan.c:1893
 do_scsi_scan_host drivers/scsi/scsi_scan.c:2032 [inline]
 do_scan_async+0x124/0x760 drivers/scsi/scsi_scan.c:2042
 async_run_entry_fn+0xa8/0x3f0 kernel/async.c:129
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888027bd1680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888027bd1700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888027bd1780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888027bd1800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888027bd1880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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