==================================================================
BUG: KASAN: null-ptr-deref in mcp2221_raw_event+0xc1f/0x1030 drivers/hid/hid-mcp2221.c:910
Write of size 77 at addr 0000000000000000 by task udevd/5212

CPU: 0 UID: 0 PID: 5212 Comm: udevd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189
 __asan_memcpy+0x3c/0x60 mm/kasan/shadow.c:106
 mcp2221_raw_event+0xc1f/0x1030 drivers/hid/hid-mcp2221.c:910
 __hid_input_report.constprop.0+0x311/0x450 drivers/hid/hid-core.c:2130
 hid_irq_in+0x35e/0x870 drivers/hid/usbhid/hid-core.c:286
 __usb_hcd_giveback_urb+0x388/0x610 drivers/usb/core/hcd.c:1661
 usb_hcd_giveback_urb+0x39b/0x450 drivers/usb/core/hcd.c:1745
 dummy_timer+0x1814/0x3a30 drivers/usb/gadget/udc/dummy_hcd.c:1995
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x1ff/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1842
 handle_softirqs+0x208/0x8d0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xfa/0x160 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+0x90/0xb0 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:unwind_next_frame+0xdfb/0x20a0 arch/x86/kernel/unwind_orc.c:641
Code: 0f 9e c7 40 84 f6 40 0f 95 c6 40 84 f7 0f 85 dc 11 00 00 83 e0 07 38 c2 40 0f 9e c6 84 d2 0f 95 c0 40 84 c6 0f 85 c5 11 00 00 <0f> b6 41 04 c0 e8 04 3c 01 0f 84 41 07 00 00 3c 04 0f 84 61 06 00
RSP: 0018:ffffc900041bf4e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff8b054102
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffc900041bf5a0 R08: ffffffff8b054106 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000000dbf1 R12: ffffc900041bf5a8
R13: ffffc900041bf558 R14: ffffc900041bf8b8 R15: ffffc900041bf58c
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 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+0x3e/0x50 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kmem_cache_free+0x2a0/0x470 mm/slub.c:4782
 skb_kfree_head net/core/skbuff.c:1045 [inline]
 skb_kfree_head net/core/skbuff.c:1042 [inline]
 skb_free_head+0x1b7/0x210 net/core/skbuff.c:1059
 skb_release_data+0x795/0x9e0 net/core/skbuff.c:1086
 skb_release_all net/core/skbuff.c:1151 [inline]
 __kfree_skb net/core/skbuff.c:1165 [inline]
 consume_skb net/core/skbuff.c:1397 [inline]
 consume_skb+0xbf/0x100 net/core/skbuff.c:1391
 netlink_recvmsg+0x51b/0x9c0 net/netlink/af_netlink.c:1974
 sock_recvmsg_nosec net/socket.c:1065 [inline]
 sock_recvmsg+0x1f9/0x250 net/socket.c:1087
 ____sys_recvmsg+0x218/0x6b0 net/socket.c:2834
 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2876
 __sys_recvmsg+0x16a/0x220 net/socket.c:2909
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b6f4bc407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffde67f5f50 EFLAGS: 00000202 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007f5b6f3ce880 RCX: 00007f5b6f4bc407
RDX: 0000000000000000 RSI: 00007ffde67f5fe0 RDI: 000000000000000c
RBP: 000055b713d112c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055b713d14750
R13: 00007ffde67f60a0 R14: 00007ffde67f5fec R15: 0000000000000000
 </TASK>
==================================================================
----------------
Code disassembly (best guess):
   0:	0f 9e c7             	setle  %bh
   3:	40 84 f6             	test   %sil,%sil
   6:	40 0f 95 c6          	setne  %sil
   a:	40 84 f7             	test   %sil,%dil
   d:	0f 85 dc 11 00 00    	jne    0x11ef
  13:	83 e0 07             	and    $0x7,%eax
  16:	38 c2                	cmp    %al,%dl
  18:	40 0f 9e c6          	setle  %sil
  1c:	84 d2                	test   %dl,%dl
  1e:	0f 95 c0             	setne  %al
  21:	40 84 c6             	test   %al,%sil
  24:	0f 85 c5 11 00 00    	jne    0x11ef
* 2a:	0f b6 41 04          	movzbl 0x4(%rcx),%eax <-- trapping instruction
  2e:	c0 e8 04             	shr    $0x4,%al
  31:	3c 01                	cmp    $0x1,%al
  33:	0f 84 41 07 00 00    	je     0x77a
  39:	3c 04                	cmp    $0x4,%al
  3b:	0f                   	.byte 0xf
  3c:	84 61 06             	test   %ah,0x6(%rcx)