==================================================================
BUG: KASAN: use-after-free in mcp2221_raw_event+0x103c/0x10a0 drivers/hid/hid-mcp2221.c:948
Read of size 1 at addr ffff88811aeeffff by task syz.2.1296/10276
CPU: 1 UID: 0 PID: 10276 Comm: syz.2.1296 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+0x156/0x4c9 mm/kasan/report.c:482
kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
mcp2221_raw_event+0x103c/0x10a0 drivers/hid/hid-mcp2221.c:948
__hid_input_report.constprop.0+0x314/0x460 drivers/hid/hid-core.c:2139
hid_irq_in+0x52e/0x6b0 drivers/hid/usbhid/hid-core.c:286
__usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657
usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741
dummy_timer+0xd85/0x3670 drivers/usb/gadget/udc/dummy_hcd.c:1995
__run_hrtimer kernel/time/hrtimer.c:1785 [inline]
__hrtimer_run_queues+0x50e/0xa70 kernel/time/hrtimer.c:1849
hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1866
handle_softirqs+0x1de/0x9d0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xed/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__rcu_read_unlock+0xd1/0x5e0 kernel/rcu/tree_plugin.h:445
Code: 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 8b 01 00 00 8b 83 fc 03 00 00 3d ff ff ff 3f 0f 87 67 01 00 00 5b 5d 41 5c <41> 5d 41 5e 41 5f e9 d4 62 d3 05 65 44 8b 25 5c c8 5c 0b 41 f7 c4
RSP: 0018:ffffc9001374f4a0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffc9001374f484
RDX: 0000000000000000 RSI: ffffffff88ffc446 RDI: ffff888113c720fc
RBP: 00007f06691fce00 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff819cfe70
R13: ffffc9001374f5d8 R14: 0000000000000000 R15: ffff888113c71d00
rcu_read_unlock include/linux/rcupdate.h:883 [inline]
is_bpf_text_address+0x94/0x1a0 kernel/bpf/core.c:750
kernel_text_address kernel/extable.c:125 [inline]
kernel_text_address+0x8d/0x100 kernel/extable.c:94
__kernel_text_address+0xd/0x30 kernel/extable.c:79
unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:385
arch_stack_walk+0xa6/0xf0 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_record_aux_stack+0x8c/0xa0 mm/kasan/generic.c:556
__call_rcu_common.constprop.0+0xa5/0x9b0 kernel/rcu/tree.c:3131
dentry_free+0xc2/0x170 fs/dcache.c:443
__dentry_kill+0x49a/0x600 fs/dcache.c:689
finish_dput+0x76/0x480 fs/dcache.c:879
dput.part.0+0x456/0x570 fs/dcache.c:928
dput+0x1f/0x30 fs/dcache.c:920
handle_mounts fs/namei.c:1748 [inline]
step_into_slowpath+0xc53/0xf90 fs/namei.c:2101
step_into fs/namei.c:2149 [inline]
open_last_lookups fs/namei.c:4618 [inline]
path_openat+0xf95/0x31a0 fs/namei.c:4827
do_file_open+0x20e/0x430 fs/namei.c:4859
do_sys_openat2+0x10d/0x1e0 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0x7b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f06691fcece
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f0667c75b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0667c766c0 RCX: 00007f06691fcece
RDX: 0000000000000002 RSI: 00007f0667c75c00 RDI: ffffffffffffff9c
RBP: 00007f06692d2b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f06694b6128 R14: 00007f06694b6090 R15: 00007ffd575e4d28
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888100000000 pfn:0x11aeef
flags: 0x200000000000000(node=0|zone=2)
raw: 0200000000000000 dead000000000100 dead000000000122 0000000000000000
raw: ffff888100000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x440dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO|__GFP_COMP), pid 5766, tgid 5766 (syz.1.139), ts 157670401049, free_ts 160727616332
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0xf10/0x39f0 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x273/0x2860 mm/page_alloc.c:5250
alloc_pages_mpol+0xe8/0x410 mm/mempolicy.c:2484
alloc_frozen_pages_noprof mm/mempolicy.c:2555 [inline]
alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2575
pagetable_alloc_noprof include/linux/mm.h:3404 [inline]
pmd_alloc_one_noprof include/asm-generic/pgalloc.h:143 [inline]
__pmd_alloc+0x3b/0x990 mm/memory.c:6709
pmd_alloc include/linux/mm.h:3320 [inline]
__handle_mm_fault+0xec4/0x2de0 mm/memory.c:6406
handle_mm_fault+0x36d/0xa20 mm/memory.c:6623
do_user_addr_fault+0x5ae/0x11d0 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x66/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
page last free pid 0 tgid 0 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
__free_frozen_pages+0x7b1/0xfb0 mm/page_alloc.c:2978
__pagetable_free include/linux/mm.h:3414 [inline]
pagetable_free include/linux/mm.h:3438 [inline]
pagetable_dtor_free include/linux/mm.h:3542 [inline]
__tlb_remove_table include/asm-generic/tlb.h:221 [inline]
__tlb_remove_table_free mm/mmu_gather.c:228 [inline]
tlb_remove_table_rcu+0x2b2/0x390 mm/mmu_gather.c:291
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869
handle_softirqs+0x1de/0x9d0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xed/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
Memory state around the buggy address:
ffff88811aeefe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88811aeeff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88811aeeff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88811aef0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88811aef0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: 48 89 f8 mov %rdi,%rax
3: 83 e0 07 and $0x7,%eax
6: 83 c0 03 add $0x3,%eax
9: 38 d0 cmp %dl,%al
b: 7c 08 jl 0x15
d: 84 d2 test %dl,%dl
f: 0f 85 8b 01 00 00 jne 0x1a0
15: 8b 83 fc 03 00 00 mov 0x3fc(%rbx),%eax
1b: 3d ff ff ff 3f cmp $0x3fffffff,%eax
20: 0f 87 67 01 00 00 ja 0x18d
26: 5b pop %rbx
27: 5d pop %rbp
28: 41 5c pop %r12
* 2a: 41 5d pop %r13 <-- trapping instruction
2c: 41 5e pop %r14
2e: 41 5f pop %r15
30: e9 d4 62 d3 05 jmp 0x5d36309
35: 65 44 8b 25 5c c8 5c mov %gs:0xb5cc85c(%rip),%r12d # 0xb5cc899
3c: 0b
3d: 41 rex.B
3e: f7 .byte 0xf7
3f: c4 .byte 0xc4