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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 ffff88807a59d5f8 by task kbnepd bnep0/7263

CPU: 1 PID: 7263 Comm: kbnepd bnep0 Not tainted 6.9.0-rc5-syzkaller #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+0x11d9/0x16a0 net/core/dev.c:11135
 unregister_netdevice_many net/core/dev.c:11163 [inline]
 unregister_netdevice_queue net/core/dev.c:11042 [inline]
 unregister_netdevice include/linux/netdevice.h:3115 [inline]
 unregister_netdev+0x1b0/0x220 net/core/dev.c:11181
 bnep_session+0x2b95/0x2d80 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:0x7a59d
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 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 7222, tgid -1876322151 (syz-executor.0), ts 7222, free_ts 256070563332
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x33de/0x3570 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6b0 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 __kmalloc_large_node+0x91/0x1e0 mm/slub.c:3911
 __do_kmalloc_node mm/slub.c:3954 [inline]
 __kmalloc+0x31b/0x460 mm/slub.c:3979
 kmalloc include/linux/slab.h:632 [inline]
 kzalloc include/linux/slab.h:749 [inline]
 hci_alloc_dev_priv+0x27/0x2030 net/bluetooth/hci_core.c:2500
 hci_alloc_dev include/net/bluetooth/hci_core.h:1672 [inline]
 __vhci_create_device drivers/bluetooth/hci_vhci.c:406 [inline]
 vhci_create_device+0x12e/0x720 drivers/bluetooth/hci_vhci.c:480
 vhci_get_user drivers/bluetooth/hci_vhci.c:537 [inline]
 vhci_write+0x3cb/0x480 drivers/bluetooth/hci_vhci.c:617
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa84/0xcb0 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x88/0x170 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
page last free pid 7222 tgid 7222 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+0x96d/0xa80 mm/page_alloc.c:2347
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
 __folio_put_large+0x13f/0x190 mm/swap.c:132
 __folio_put+0x299/0x390 mm/swap.c:140
 folio_put include/linux/mm.h:1506 [inline]
 free_large_kmalloc+0x103/0x1c0 mm/slub.c:4361
 kfree+0x1a9/0x370 mm/slub.c:4384
 hci_release_dev+0x1516/0x16a0 net/bluetooth/hci_core.c:2833
 bt_host_release+0x83/0x90 net/bluetooth/hci_sysfs.c:94
 device_release+0x99/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22b/0x480 lib/kobject.c:737
 vhci_release+0x8b/0xd0 drivers/bluetooth/hci_vhci.c:675
 __fput+0x429/0x8a0 fs/file_table.c:422
 task_work_run+0x24f/0x310 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xa1b/0x27d0 kernel/exit.c:878
 do_group_exit+0x207/0x2c0 kernel/exit.c:1027
 __do_sys_exit_group kernel/exit.c:1038 [inline]
 __se_sys_exit_group kernel/exit.c:1036 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036

Memory state around the buggy address:
 ffff88807a59d480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807a59d500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807a59d580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff88807a59d600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807a59d680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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