syzbot

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BUG: KASAN: slab-use-after-free in cfusbl_device_notify+0x883/0x900 net/caif/caif_usb.c:142
Read of size 8 at addr ffff888057ea8c50 by task syz.0.983/8232

CPU: 1 UID: 0 PID: 8232 Comm: syz.0.983 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 cfusbl_device_notify+0x883/0x900 net/caif/caif_usb.c:142
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 register_netdevice+0xe02/0x2270 net/core/dev.c:11201
 register_netdev+0x34/0x50 net/core/dev.c:11322
 bnep_add_connection+0x71c/0xd20 net/bluetooth/bnep/core.c:624
 do_bnep_sock_ioctl.constprop.0+0x496/0x590 net/bluetooth/bnep/sock.c:83
 sock_do_ioctl+0x118/0x280 net/socket.c:1238
 sock_ioctl+0x227/0x6b0 net/socket.c:1359
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9bc738ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9bc819b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9bc75c5fa0 RCX: 00007f9bc738ebe9
RDX: 0000200000000000 RSI: 00000000400442c8 RDI: 0000000000000005
RBP: 00007f9bc7411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9bc75c6038 R14: 00007f9bc75c5fa0 R15: 00007fffbd184b48
 </TASK>

Allocated by task 5848:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __hci_conn_add+0x130/0x1bd0 net/bluetooth/hci_conn.c:949
 hci_conn_add_unset+0x6d/0x100 net/bluetooth/hci_conn.c:1061
 hci_conn_request_evt+0x88a/0xaf0 net/bluetooth/hci_event.c:3288
 hci_event_func net/bluetooth/hci_event.c:7545 [inline]
 hci_event_packet+0xa0d/0x11c0 net/bluetooth/hci_event.c:7599
 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4071
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5172:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x60/0x70 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+0x2b4/0x4d0 mm/slub.c:4894
 device_release+0xa4/0x240 drivers/base/core.c:2565
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1e7/0x5a0 lib/kobject.c:737
 put_device drivers/base/core.c:3797 [inline]
 device_unregister+0x2f/0xc0 drivers/base/core.c:3920
 hci_conn_del_sysfs+0xb4/0x180 net/bluetooth/hci_sysfs.c:79
 hci_conn_cleanup net/bluetooth/hci_conn.c:173 [inline]
 hci_conn_del+0x657/0x1180 net/bluetooth/hci_conn.c:1211
 hci_conn_hash_flush+0x186/0x260 net/bluetooth/hci_conn.c:2600
 hci_dev_close_sync+0x602/0x11d0 net/bluetooth/hci_sync.c:5294
 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:501
 hci_error_reset+0xbf/0x320 net/bluetooth/hci_core.c:1034
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548
 insert_work+0x36/0x230 kernel/workqueue.c:2184
 __queue_work+0x97e/0x1160 kernel/workqueue.c:2339
 __queue_delayed_work+0x35b/0x460 kernel/workqueue.c:2507
 queue_delayed_work_on+0x1b5/0x200 kernel/workqueue.c:2559
 queue_delayed_work include/linux/workqueue.h:684 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1675 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1649 [inline]
 l2cap_chan_del+0x5a0/0x8f0 net/bluetooth/l2cap_core.c:671
 l2cap_conn_del+0x37a/0x730 net/bluetooth/l2cap_core.c:1787
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7325 [inline]
 l2cap_disconn_cfm+0x96/0xd0 net/bluetooth/l2cap_core.c:7318
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2097 [inline]
 hci_conn_hash_flush+0x10b/0x260 net/bluetooth/hci_conn.c:2599
 hci_dev_close_sync+0x602/0x11d0 net/bluetooth/hci_sync.c:5294
 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:501
 hci_error_reset+0xbf/0x320 net/bluetooth/hci_core.c:1034
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888057ea8000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 3152 bytes inside of
 freed 8192-byte region [ffff888057ea8000, ffff888057eaa000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x57ea8
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 ffff88801b842280 ffffea00006e6e00 dead000000000002
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b842280 ffffea00006e6e00 dead000000000002
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea00015faa01 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5850, tgid 5850 (syz-executor), ts 71969227049, free_ts 17878622499
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab mm/slub.c:2660 [inline]
 new_slab+0x247/0x330 mm/slub.c:2714
 ___slab_alloc+0xcf2/0x1750 mm/slub.c:3901
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3992
 __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_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4395
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:600
 __alloc_skb+0x166/0x380 net/core/skbuff.c:669
 alloc_skb include/linux/skbuff.h:1336 [inline]
 netlink_dump+0x644/0xd30 net/netlink/af_netlink.c:2286
 __netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2442
 genl_family_rcv_msg_dumpit+0x1e2/0x2e0 net/netlink/genetlink.c:1076
 genl_family_rcv_msg net/netlink/genetlink.c:1192 [inline]
 genl_rcv_msg+0x46e/0x800 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895
 __free_pages mm/page_alloc.c:5260 [inline]
 free_contig_range+0x183/0x4b0 mm/page_alloc.c:7091
 destroy_args+0x794/0xc10 mm/debug_vm_pgtable.c:958
 debug_vm_pgtable+0x1a32/0x3640 mm/debug_vm_pgtable.c:1345
 do_one_initcall+0x120/0x6e0 init/main.c:1269
 do_initcall_level init/main.c:1331 [inline]
 do_initcalls init/main.c:1347 [inline]
 do_basic_setup init/main.c:1366 [inline]
 kernel_init_freeable+0x5c2/0x910 init/main.c:1579
 kernel_init+0x1c/0x2b0 init/main.c:1469
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888057ea8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888057ea8b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888057ea8c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888057ea8c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888057ea8d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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