syzbot

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BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
Read of size 1 at addr ffff8880318ca330 by task kworker/1:8/10951

CPU: 1 UID: 0 PID: 10951 Comm: kworker/1:8 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x84/0x350 kernel/locking/lockdep.c:5844
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
 rt_mutex_slowunlock+0xb8/0x300 kernel/locking/rtmutex.c:1426
 process_one_work+0x9a3/0x1710 kernel/workqueue.c:3312
 process_scheduled_works kernel/workqueue.c:3403 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3489
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 60:
 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]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5415
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 l2cap_conn_add+0xaa/0x970 net/bluetooth/l2cap_core.c:7001
 l2cap_connect_cfm+0x142/0x1560 net/bluetooth/l2cap_core.c:7378
 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
 hci_remote_features_evt+0x5b9/0x950 net/bluetooth/hci_event.c:3760
 hci_event_func net/bluetooth/hci_event.c:7796 [inline]
 hci_event_packet+0x6ab/0xef0 net/bluetooth/hci_event.c:7847
 hci_rx_work+0x3ee/0x1040 net/bluetooth/hci_core.c:4077
 process_one_work+0x9a3/0x1710 kernel/workqueue.c:3312
 process_scheduled_works kernel/workqueue.c:3403 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3489
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 13989:
 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:2689 [inline]
 slab_free mm/slub.c:6246 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6561
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]
 hci_conn_hash_flush+0x10d/0x260 net/bluetooth/hci_conn.c:2734
 hci_dev_close_sync+0x821/0x10e0 net/bluetooth/hci_sync.c:5368
 hci_dev_do_close net/bluetooth/hci_core.c:502 [inline]
 hci_unregister_dev+0x21a/0x5a0 net/bluetooth/hci_core.c:2716
 vhci_release+0x155/0x1b0 drivers/bluetooth/hci_vhci.c:690
 __fput+0x461/0xa70 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x70f/0x22c0 kernel/exit.c:975
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117
 get_signal+0x1284/0x1330 kernel/signal.c:3037
 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:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 insert_work+0x3d/0x330 kernel/workqueue.c:2226
 __queue_work+0xcfd/0x1010 kernel/workqueue.c:2381
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1794 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x764/0x9f0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1155
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Second to last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 insert_work+0x3d/0x330 kernel/workqueue.c:2226
 __queue_work+0xbdb/0x1010 kernel/workqueue.c:2385
 queue_work_on+0x106/0x1d0 kernel/workqueue.c:2432
 queue_work include/linux/workqueue.h:696 [inline]
 l2cap_conn_ready net/bluetooth/l2cap_core.c:1660 [inline]
 l2cap_connect_cfm+0x10f5/0x1560 net/bluetooth/l2cap_core.c:7419
 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
 hci_remote_features_evt+0x5b9/0x950 net/bluetooth/hci_event.c:3760
 hci_event_func net/bluetooth/hci_event.c:7796 [inline]
 hci_event_packet+0x6ab/0xef0 net/bluetooth/hci_event.c:7847
 hci_rx_work+0x3ee/0x1040 net/bluetooth/hci_core.c:4077
 process_one_work+0x9a3/0x1710 kernel/workqueue.c:3312
 process_scheduled_works kernel/workqueue.c:3403 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3489
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880318ca000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 816 bytes inside of
 freed 1024-byte region [ffff8880318ca000, ffff8880318ca400)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880318cf800 pfn:0x318c8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88813fe0fdc0 ffffea00007db010 ffffea0001ad2610
raw: ffff8880318cf800 000000080010000e 00000000f5000000 0000000000000000
head: 0080000000000240 ffff88813fe0fdc0 ffffea00007db010 ffffea0001ad2610
head: ffff8880318cf800 000000080010000e 00000000f5000000 0000000000000000
head: 0080000000000003 fffffffffffffe01 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 1, tgid 1 (swapper/0), ts 17176054733, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7251
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5410
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 comedi_alloc_board_minor+0x57/0x530 drivers/comedi/comedi_fops.c:3510
 comedi_init+0x109/0x1c0 drivers/comedi/comedi_fops.c:3664
 do_one_initcall+0x250/0x870 init/main.c:1392
 do_initcall_level+0x104/0x190 init/main.c:1454
 do_initcalls+0x59/0xa0 init/main.c:1470
 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1703
 kernel_init+0x1d/0x1d0 init/main.c:1593
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8880318ca200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880318ca280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880318ca300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8880318ca380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880318ca400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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