==================================================================
BUG: KASAN: slab-use-after-free in hci_cmd_work+0x5d0/0x7b0 net/bluetooth/hci_core.c:4174
Read of size 2 at addr ffff88805e0c0678 by task kworker/u9:3/5836

CPU: 1 UID: 0 PID: 5836 Comm: kworker/u9:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: hci2 hci_cmd_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 hci_cmd_work+0x5d0/0x7b0 net/bluetooth/hci_core.c:4174
 process_one_work+0x93a/0x15e0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 5833:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4948 [inline]
 slab_alloc_node mm/slub.c:5258 [inline]
 kmem_cache_alloc_node_noprof+0x43c/0x710 mm/slub.c:5310
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:664
 alloc_skb include/linux/skbuff.h:1383 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:510 [inline]
 hci_cmd_sync_alloc+0x3d/0x3b0 net/bluetooth/hci_sync.c:58
 hci_cmd_sync_add net/bluetooth/hci_sync.c:99 [inline]
 __hci_cmd_sync_sk+0x1a7/0xc70 net/bluetooth/hci_sync.c:168
 __hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:263 [inline]
 __hci_cmd_sync_status net/bluetooth/hci_sync.c:287 [inline]
 hci_reset_sync+0x4a/0x140 net/bluetooth/hci_sync.c:3664
 hci_init1_sync net/bluetooth/hci_sync.c:3750 [inline]
 hci_init_sync net/bluetooth/hci_sync.c:4874 [inline]
 hci_dev_init_sync net/bluetooth/hci_sync.c:5066 [inline]
 hci_dev_open_sync+0xec5/0x2dc0 net/bluetooth/hci_sync.c:5144
 hci_dev_do_open net/bluetooth/hci_core.c:430 [inline]
 hci_power_on+0x1b4/0x720 net/bluetooth/hci_core.c:959
 process_one_work+0x93a/0x15e0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Freed by task 5840:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6663 [inline]
 kmem_cache_free+0x197/0x640 mm/slub.c:6774
 kfree_skb_reason include/linux/skbuff.h:1322 [inline]
 kfree_skb include/linux/skbuff.h:1331 [inline]
 vhci_read+0x49a/0x5b0 drivers/bluetooth/hci_vhci.c:593
 vfs_read+0x200/0xa30 fs/read_write.c:570
 ksys_read+0x145/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88805e0c0640
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 56 bytes inside of
 freed 240-byte region [ffff88805e0c0640, ffff88805e0c0730)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5e0c0
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff888140efca00 dead000000000122 0000000000000000
raw: 0000000000000000 00000000000c000c 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5838, tgid 5838 (syz-executor), ts 69968309861, free_ts 69966266672
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3920
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5215
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xf56/0x1990 mm/slub.c:4651
 __slab_alloc+0x65/0x100 mm/slub.c:4774
 __slab_alloc_node mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:5246 [inline]
 kmem_cache_alloc_noprof+0x40f/0x700 mm/slub.c:5265
 skb_clone+0x212/0x3a0 net/core/skbuff.c:2069
 do_one_broadcast net/netlink/af_netlink.c:1455 [inline]
 netlink_broadcast_filtered+0x6ae/0x1000 net/netlink/af_netlink.c:1533
 netlink_broadcast+0x37/0x50 net/netlink/af_netlink.c:1557
 uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
 kobject_uevent_net_broadcast+0x378/0x560 lib/kobject_uevent.c:410
 kobject_uevent_env+0x55c/0x9f0 lib/kobject_uevent.c:608
 device_add+0x557/0xb80 drivers/base/core.c:3670
 hci_register_dev+0x36c/0x8b0 net/bluetooth/hci_core.c:2621
 __vhci_create_device drivers/bluetooth/hci_vhci.c:451 [inline]
 vhci_create_device+0x39c/0x650 drivers/bluetooth/hci_vhci.c:479
page last free pid 2 tgid 2 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2948
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1b2/0x1d0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:579 [inline]
 alloc_vmap_area+0xdca/0x1500 mm/vmalloc.c:2124
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3219
 __vmalloc_node_range_noprof+0x371/0x16a0 mm/vmalloc.c:4009
 __vmalloc_node_noprof+0xc2/0x110 mm/vmalloc.c:4109
 alloc_thread_stack_node kernel/fork.c:311 [inline]
 dup_task_struct+0x3d4/0x830 kernel/fork.c:880
 copy_process+0x4ea/0x3930 kernel/fork.c:2011
 kernel_clone+0x21e/0x850 kernel/fork.c:2609
 kernel_thread+0x10d/0x160 kernel/fork.c:2670
 create_kthread kernel/kthread.c:486 [inline]
 kthreadd+0x575/0x770 kernel/kthread.c:844
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Memory state around the buggy address:
 ffff88805e0c0500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805e0c0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
>ffff88805e0c0600: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
                                                                ^
 ffff88805e0c0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805e0c0700: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
==================================================================