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BUG: KASAN: use-after-free in device_for_each_child+0xa7/0x170 drivers/base/core.c:4044
Read of size 8 at addr ffff88806229d5f8 by task kbnepd bnep0/9005

CPU: 1 PID: 9005 Comm: kbnepd bnep0 Not tainted 6.9.0-rc5-syzkaller-00175-gbef1e4c8c3e0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 device_for_each_child+0xa7/0x170 drivers/base/core.c:4044
 pm_runtime_set_memalloc_noio+0x114/0x260 drivers/base/power/runtime.c:248
 netdev_unregister_kobject+0x178/0x250 net/core/net-sysfs.c:2106
 unregister_netdevice_many_notify+0x11dd/0x16e0 net/core/dev.c:11135
 unregister_netdevice_many net/core/dev.c:11163 [inline]
 unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
 unregister_netdevice include/linux/netdevice.h:3115 [inline]
 unregister_netdev+0x1c/0x30 net/core/dev.c:11181
 bnep_session+0x2e09/0x3000 net/bluetooth/bnep/core.c:525
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x400000000 pfn:0x6229d
flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000400000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x102cc0(GFP_USER|__GFP_NOWARN), pid 9005, tgid -20890845 (kbnepd bnep0), ts 9005, free_ts 317806796188
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
 alloc_pages_mpol+0x3e8/0x680 mm/mempolicy.c:2264
 stack_depot_save_flags+0x666/0x830 lib/stackdepot.c:635
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_save_track+0x51/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc_node+0x194/0x380 mm/slub.c:3888
 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:658
 alloc_skb include/linux/skbuff.h:1313 [inline]
 nlmsg_new include/net/netlink.h:1010 [inline]
 rtmsg_ifinfo_build_skb+0x89/0x290 net/core/rtnetlink.c:4048
 unregister_netdevice_many_notify+0xe3e/0x16e0 net/core/dev.c:11109
 unregister_netdevice_many net/core/dev.c:11163 [inline]
 unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
 unregister_netdevice include/linux/netdevice.h:3115 [inline]
 lapbeth_free_device drivers/net/wan/lapbether.c:437 [inline]
 lapbeth_device_event+0x64e/0xa00 drivers/net/wan/lapbether.c:472
 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
 call_netdevice_notifiers net/core/dev.c:2002 [inline]
 unregister_netdevice_many_notify+0xd9b/0x16e0 net/core/dev.c:11105
 unregister_netdevice_many net/core/dev.c:11163 [inline]
 unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
page last free pid 9005 tgid 9005 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1141 [inline]
 free_unref_page_prepare+0x986/0xab0 mm/page_alloc.c:2347
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
 stack_depot_save_flags+0x6f6/0x830 lib/stackdepot.c:673
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_save_track+0x51/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc_node+0x194/0x380 mm/slub.c:3888
 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:658
 alloc_skb include/linux/skbuff.h:1313 [inline]
 nlmsg_new include/net/netlink.h:1010 [inline]
 rtmsg_ifinfo_build_skb+0x89/0x290 net/core/rtnetlink.c:4048
 unregister_netdevice_many_notify+0xe3e/0x16e0 net/core/dev.c:11109
 unregister_netdevice_many net/core/dev.c:11163 [inline]
 unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
 unregister_netdevice include/linux/netdevice.h:3115 [inline]
 lapbeth_free_device drivers/net/wan/lapbether.c:437 [inline]
 lapbeth_device_event+0x64e/0xa00 drivers/net/wan/lapbether.c:472
 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
 call_netdevice_notifiers net/core/dev.c:2002 [inline]
 unregister_netdevice_many_notify+0xd9b/0x16e0 net/core/dev.c:11105
 unregister_netdevice_many net/core/dev.c:11163 [inline]
 unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11042
 unregister_netdevice include/linux/netdevice.h:3115 [inline]
 unregister_netdev+0x1c/0x30 net/core/dev.c:11181
 bnep_session+0x2e09/0x3000 net/bluetooth/bnep/core.c:525

Memory state around the buggy address:
 ffff88806229d480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806229d500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806229d580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff88806229d600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806229d680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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