==================================================================
BUG: KASAN: use-after-free in mcp2221_raw_event+0xfcd/0x1190 drivers/hid/hid-mcp2221.c:854
Read of size 1 at addr ffff888047513fff by task swapper/1/0

CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.16.0-rc3-syzkaller-00233-g35e261cd95dd #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 mcp2221_raw_event+0xfcd/0x1190 drivers/hid/hid-mcp2221.c:854
 __hid_input_report drivers/hid/hid-core.c:2117 [inline]
 hid_input_report+0x407/0x520 drivers/hid/hid-core.c:2144
 hid_irq_in+0x47e/0x6d0 drivers/hid/usbhid/hid-core.c:286
 __usb_hcd_giveback_urb+0x417/0x690 drivers/usb/core/hcd.c:1650
 dummy_timer+0x862/0x4550 drivers/usb/gadget/udc/dummy_hcd.c:1995
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x529/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1842
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:sched_core_balance+0x156/0xf00 kernel/sched/core.c:6427
Code: 67 8a 8b e8 ac 4a 0b 00 4c 89 74 24 68 4c 89 7c 24 48 e9 3b 0d 00 00 4c 89 f7 e8 45 82 d6 09 e8 70 d8 34 00 fb 48 8b 5c 24 70 <83> fb 08 0f 83 06 0d 00 00 4c 8d 34 dd 60 7c ba 8d 4c 89 f0 48 c1
RSP: 0018:ffffc900001979e0 EFLAGS: 00000282
RAX: c160aa89e232a300 RBX: 0000000000000001 RCX: c160aa89e232a300
RDX: 0000000000000000 RSI: ffffffff8d9821e9 RDI: ffffffff8be28f00
RBP: ffffc90000197b48 R08: ffffffff8fa109f7 R09: 1ffffffff1f4213e
R10: dffffc0000000000 R11: fffffbfff1f4213f R12: ffff8880b8739f80
R13: dffffc0000000000 R14: ffff8880b8739f80 R15: 0000000000000001
 do_balance_callbacks kernel/sched/core.c:5042 [inline]
 __balance_callbacks kernel/sched/core.c:5096 [inline]
 finish_lock_switch kernel/sched/core.c:5143 [inline]
 finish_task_switch+0x3a4/0x950 kernel/sched/core.c:5262
 context_switch kernel/sched/core.c:5399 [inline]
 __schedule+0x16fd/0x4d00 kernel/sched/core.c:6785
 schedule_idle+0x52/0x90 kernel/sched/core.c:6904
 do_idle+0x4ad/0x510 kernel/sched/idle.c:353
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x147
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x200000f4b pfn:0x47513
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000200000f4b 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 17610, tgid 17608 (syz.0.2308), ts 1494404290888, free_ts 1545649223325
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_node_track_caller_noprof+0x2f8/0x4e0 mm/slub.c:4347
 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:601
 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
 alloc_skb include/linux/skbuff.h:1336 [inline]
 alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6665
 sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2999
 unix_dgram_sendmsg+0x4f6/0x1870 net/unix/af_unix.c:2083
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:727
 ____sys_sendmsg+0x52d/0x830 net/socket.c:2566
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
 __sys_sendmmsg+0x227/0x430 net/socket.c:2709
page last free pid 5187 tgid 5187 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706
 __slab_free+0x326/0x400 mm/slub.c:4554
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4249
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
 alloc_skb include/linux/skbuff.h:1336 [inline]
 alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6665
 sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2999
 unix_dgram_sendmsg+0x4f6/0x1870 net/unix/af_unix.c:2083
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:727
 __sys_sendto+0x3bd/0x520 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2183
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888047513e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888047513f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888047513f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff888047514000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888047514080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	67 8a 8b e8 ac 4a 0b 	mov    0xb4aace8(%ebx),%cl
   7:	00 4c 89 74          	add    %cl,0x74(%rcx,%rcx,4)
   b:	24 68                	and    $0x68,%al
   d:	4c 89 7c 24 48       	mov    %r15,0x48(%rsp)
  12:	e9 3b 0d 00 00       	jmp    0xd52
  17:	4c 89 f7             	mov    %r14,%rdi
  1a:	e8 45 82 d6 09       	call   0x9d68264
  1f:	e8 70 d8 34 00       	call   0x34d894
  24:	fb                   	sti
  25:	48 8b 5c 24 70       	mov    0x70(%rsp),%rbx
* 2a:	83 fb 08             	cmp    $0x8,%ebx <-- trapping instruction
  2d:	0f 83 06 0d 00 00    	jae    0xd39
  33:	4c 8d 34 dd 60 7c ba 	lea    -0x724583a0(,%rbx,8),%r14
  3a:	8d
  3b:	4c 89 f0             	mov    %r14,%rax
  3e:	48                   	rex.W
  3f:	c1                   	.byte 0xc1