syzbot

==================================================================
BUG: KASAN: slab-use-after-free in cfusbl_device_notify+0x16b/0x6b0 net/caif/caif_usb.c:142
Read of size 8 at addr ffff888036828dc8 by task syz.5.5116/31772

CPU: 0 UID: 0 PID: 31772 Comm: syz.5.5116 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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
 cfusbl_device_notify+0x16b/0x6b0 net/caif/caif_usb.c:142
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline]
 call_netdevice_notifiers net/core/dev.c:2295 [inline]
 register_netdevice+0x1341/0x1cf0 net/core/dev.c:11464
 register_netdev+0x40/0x60 net/core/dev.c:11522
 bnep_add_connection+0x6e5/0xca0 net/bluetooth/bnep/core.c:624
 do_bnep_sock_ioctl+0x40b/0x650 net/bluetooth/bnep/sock.c:83
 sock_do_ioctl+0x101/0x320 net/socket.c:1254
 sock_ioctl+0x5c9/0x7f0 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f860b1ebf79
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:00007f860943e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f860b465fa0 RCX: 00007f860b1ebf79
RDX: 00002000000000c0 RSI: 00000000400442c8 RDI: 0000000000000005
RBP: 00007f860b2827e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f860b466038 R14: 00007f860b465fa0 R15: 00007fff1b910978
 </TASK>

Allocated by task 20910:
 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:5297
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 __hci_conn_add+0x3c5/0x1b40 net/bluetooth/hci_conn.c:963
 hci_conn_request_evt+0x5b1/0xc40 net/bluetooth/hci_event.c:3299
 hci_event_func net/bluetooth/hci_event.c:7719 [inline]
 hci_event_packet+0x805/0x12c0 net/bluetooth/hci_event.c:7773
 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4076
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 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 31772:
 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:2670 [inline]
 slab_free mm/slub.c:6082 [inline]
 kfree+0x1c1/0x690 mm/slub.c:6399
 device_release+0x9e/0x1d0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x228/0x560 lib/kobject.c:737
 put_device drivers/base/core.c:3797 [inline]
 device_add+0x6bb/0xb80 drivers/base/core.c:3742
 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2358
 register_netdevice+0x12b7/0x1cf0 net/core/dev.c:11406
 register_netdev+0x40/0x60 net/core/dev.c:11522
 bnep_add_connection+0x6e5/0xca0 net/bluetooth/bnep/core.c:624
 do_bnep_sock_ioctl+0x40b/0x650 net/bluetooth/bnep/sock.c:83
 sock_do_ioctl+0x101/0x320 net/socket.c:1254
 sock_ioctl+0x5c9/0x7f0 net/socket.c:1375
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 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:2199
 __queue_work+0xcfd/0xff0 kernel/workqueue.c:2354
 queue_delayed_work_on+0x11a/0x1e0 kernel/workqueue.c:2574
 l2cap_chan_del+0x285/0x610 net/bluetooth/l2cap_core.c:672
 l2cap_conn_del+0x326/0x5b0 net/bluetooth/l2cap_core.c:1788
 l2cap_connect_cfm+0x12b/0x13e0 net/bluetooth/l2cap_core.c:7260
 hci_connect_cfm include/net/bluetooth/hci_core.h:2131 [inline]
 hci_conn_failed+0x1ce/0x340 net/bluetooth/hci_conn.c:1336
 hci_abort_conn_sync+0xdd0/0x1190 net/bluetooth/hci_sync.c:5722
 hci_cmd_sync_work+0x213/0x400 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 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:2199
 __queue_work+0xcfd/0xff0 kernel/workqueue.c:2354
 call_timer_fn+0x192/0x5a0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1794 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x764/0x9f0 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
 handle_softirqs+0x1de/0x640 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1138
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 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 ffff888036828000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 3528 bytes inside of
 freed 8192-byte region [ffff888036828000, ffff88803682a000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x36828
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 ffff88813fe0e280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe0e280 dead000000000100 dead000000000122
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000da0a01 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 14554, tgid 14551 (syz.4.2573), ts 918478743726, free_ts 918458684148
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3950
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5245
 alloc_slab_page mm/slub.c:3238 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3411
 new_slab mm/slub.c:3469 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7091
 refill_sheaf mm/slub.c:2787 [inline]
 __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4536
 alloc_from_pcs mm/slub.c:4639 [inline]
 slab_alloc_node mm/slub.c:4773 [inline]
 __do_kmalloc_node mm/slub.c:5176 [inline]
 __kmalloc_noprof+0x530/0x7b0 mm/slub.c:5189
 kmalloc_noprof include/linux/slab.h:966 [inline]
 kmalloc_array_noprof include/linux/slab.h:1113 [inline]
 snd_seq_oss_readq_new+0x81/0x260 sound/core/seq/oss/seq_oss_readq.c:41
 snd_seq_oss_open+0x821/0xfc0 sound/core/seq/oss/seq_oss_init.c:226
 odev_open+0x67/0xd0 sound/core/seq/oss/seq_oss.c:128
 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:411
 do_dentry_open+0x83d/0x13e0 fs/open.c:949
 vfs_open+0x3b/0x350 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2e3d/0x38a0 fs/namei.c:4830
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
page last free pid 9698 tgid 9698 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xfd0/0x1160 mm/page_alloc.c:2973
 __slab_free+0x24f/0x2a0 mm/slub.c:5490
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4459 [inline]
 slab_alloc_node mm/slub.c:4788 [inline]
 __do_kmalloc_node mm/slub.c:5176 [inline]
 __kmalloc_noprof+0x399/0x7b0 mm/slub.c:5189
 kmalloc_noprof include/linux/slab.h:966 [inline]
 kmalloc_array_noprof include/linux/slab.h:1113 [inline]
 security_inode_init_security+0x102/0x3d0 security/security.c:1321
 shmem_mknod+0x1fe/0x360 mm/shmem.c:3908
 shmem_mkdir+0x33/0x70 mm/shmem.c:3962
 vfs_mkdir+0x40b/0x630 fs/namei.c:5233
 filename_mkdirat+0x289/0x520 fs/namei.c:5266
 __do_sys_mkdirat fs/namei.c:5287 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5284
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888036828c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888036828d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888036828d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff888036828e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888036828e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================