==================================================================
BUG: KASAN: use-after-free in mcp2221_raw_event+0x110d/0x1140 drivers/hid/hid-mcp2221.c:975
Read of size 1 at addr ffff88811a65ffff by task pr/ttyS0/15
CPU: 0 UID: 0 PID: 15 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
mcp2221_raw_event+0x110d/0x1140 drivers/hid/hid-mcp2221.c:975
__hid_input_report.constprop.0+0x319/0x470 drivers/hid/hid-core.c:2175
hid_irq_in+0x55d/0x710 drivers/hid/usbhid/hid-core.c:287
__usb_hcd_giveback_urb+0x38e/0x610 drivers/usb/core/hcd.c:1657
usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741
dummy_timer+0xdb2/0x3700 drivers/usb/gadget/udc/dummy_hcd.c:2019
__run_hrtimer kernel/time/hrtimer.c:2067 [inline]
__hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2124
hrtimer_run_softirq+0x1ca/0x360 kernel/time/hrtimer.c:2141
handle_softirqs+0x1d9/0x9b0 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
invoke_softirq kernel/softirq.c:519 [inline]
__irq_exit_rcu+0x168/0x210 kernel/softirq.c:758
irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:221
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 56 f7 05 fa 48 89 df e8 de 4d 06 fa f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 65 a3 f8 f9 65 48 83 3d d4 ee 98 05 00 74 16 5b
RSP: 0018:ffffc900000ffcb8 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffffffff9448a7e0 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff89329b79 RDI: ffffffff87d2b780
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 205d343631315420 R12: 1ffff9200001ff9a
R13: ffffffff89eb8ae0 R14: 0000000000000001 R15: 0000000000000000
nbcon_emit_one+0x15c/0x2b0 kernel/printk/nbcon.c:1165
nbcon_kthread_func+0x613/0x7d0 kernel/printk/nbcon.c:1271
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11a65f
flags: 0x200000000000000(node=0|zone=2)
raw: 0200000000000000 0000000000000000 00000000ffffffff 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2870, tgid 2870 (udevd), ts 22432583349
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0xf4b/0x3440 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x2d7/0x2f70 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab mm/slub.c:3462 [inline]
new_slab+0xa9/0x6e0 mm/slub.c:3513
refill_objects+0xe3/0x410 mm/slub.c:7410
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
kmem_cache_alloc_noprof+0x471/0x650 mm/slub.c:5010
alloc_empty_file+0x5b/0x1c0 fs/file_table.c:262
path_openat+0xdb/0x2440 fs/namei.c:4986
do_file_open+0x20e/0x430 fs/namei.c:5029
do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
do_sys_open fs/open.c:1423 [inline]
__do_sys_openat fs/open.c:1439 [inline]
__se_sys_openat fs/open.c:1434 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1434
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x119/0x710 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 2859 tgid 2859 ts 204612951661 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0x714/0xfc0 mm/page_alloc.c:2962
rcu_do_batch kernel/rcu/tree.c:2650 [inline]
rcu_core+0x5f0/0x1260 kernel/rcu/tree.c:2919
handle_softirqs+0x1d9/0x9b0 kernel/softirq.c:645
do_softirq kernel/softirq.c:546 [inline]
do_softirq+0xaf/0xf0 kernel/softirq.c:533
__local_bh_enable_ip+0xff/0x120 kernel/softirq.c:473
local_bh_enable include/linux/bottom_half.h:33 [inline]
__alloc_skb+0x5db/0x710 net/core/skbuff.c:699
alloc_skb include/linux/skbuff.h:1384 [inline]
alloc_skb_with_frags+0xdd/0x760 net/core/skbuff.c:6789
sock_alloc_send_pskb+0x801/0x980 net/core/sock.c:3015
unix_dgram_sendmsg+0x3c7/0x1810 net/unix/af_unix.c:2144
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
__sys_sendto+0x48b/0x4e0 net/socket.c:2281
__do_sys_sendto net/socket.c:2288 [inline]
__se_sys_sendto net/socket.c:2284 [inline]
__x64_sys_sendto+0xe0/0x1c0 net/socket.c:2284
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x119/0x710 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88811a65fe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88811a65ff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88811a65ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88811a660000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88811a660080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: f5 cmc
1: 53 push %rbx
2: 48 8b 74 24 10 mov 0x10(%rsp),%rsi
7: 48 89 fb mov %rdi,%rbx
a: 48 83 c7 18 add $0x18,%rdi
e: e8 56 f7 05 fa call 0xfa05f769
13: 48 89 df mov %rbx,%rdi
16: e8 de 4d 06 fa call 0xfa064df9
1b: f7 c5 00 02 00 00 test $0x200,%ebp
21: 75 23 jne 0x46
23: 9c pushf
24: 58 pop %rax
25: f6 c4 02 test $0x2,%ah
28: 75 37 jne 0x61
* 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction
2f: e8 65 a3 f8 f9 call 0xf9f8a399
34: 65 48 83 3d d4 ee 98 cmpq $0x0,%gs:0x598eed4(%rip) # 0x598ef11
3b: 05 00
3d: 74 16 je 0x55
3f: 5b pop %rbx