==================================================================
BUG: KASAN: use-after-free in mcp2221_raw_event+0x106a/0x1240 drivers/hid/hid-mcp2221.c:948
Read of size 1 at addr ffff88804f9d7fff by task kworker/u8:14/6146
CPU: 0 UID: 0 PID: 6146 Comm: kworker/u8:14 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: bat_events batadv_mcast_mla_update
Call Trace:
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
mcp2221_raw_event+0x106a/0x1240 drivers/hid/hid-mcp2221.c:948
__hid_input_report drivers/hid/hid-core.c:2139 [inline]
hid_input_report+0x41d/0x580 drivers/hid/hid-core.c:2166
hid_irq_in+0x47e/0x6d0 drivers/hid/usbhid/hid-core.c:286
__usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1661
dummy_timer+0x85f/0x45b0 drivers/usb/gadget/udc/dummy_hcd.c:1995
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1858
handle_softirqs+0x27d/0x850 kernel/softirq.c:626
__do_softirq kernel/softirq.c:660 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727
irq_exit_rcu+0x9/0x30 kernel/softirq.c:743
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:lock_acquire+0xd1/0x340 kernel/locking/lockdep.c:5864
Code: 7e 92 83 b8 2c 0b 00 00 00 0f 85 d5 00 00 00 48 c7 44 24 30 00 00 00 00 9c 8f 44 24 30 4c 89 74 24 10 4d 89 fe 4c 8b 7c 24 30 48 c7 c7 93 5c 7a 8d e8 a2 f6 bc 09 65 ff 05 2b 5d e0 10 45 31
RSP: 0018:ffffc9000b64f7e0 EFLAGS: 00000246
RAX: ffff888024e80000 RBX: 0000000000000000 RCX: 91a0b07b8b192700
RDX: 0000000000000000 RSI: ffffffff8b2829ff RDI: 1ffffffff1be833c
RBP: ffffffff8b282579 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1005fc9ad0 R12: 0000000000000002
R13: ffffffff8df419e0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
batadv_mcast_mla_forw_flags_get net/batman-adv/multicast.c:251 [inline]
batadv_mcast_mla_flags_get net/batman-adv/multicast.c:287 [inline]
__batadv_mcast_mla_update net/batman-adv/multicast.c:907 [inline]
batadv_mcast_mla_update+0x5ff/0x3600 net/batman-adv/multicast.c:946
process_one_work+0x93a/0x15a0 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
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x8 pfn:0x4f9d7
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000008 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 0x100cc2(GFP_HIGHUSER), pid 8209, tgid 8208 (syz.3.826), ts 157002937792, free_ts 157727453325
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
prep_new_page mm/page_alloc.c:1854 [inline]
get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2577
kimage_alloc_pages+0xbd/0x3b0 kernel/kexec_core.c:285
kimage_alloc_page+0xab/0x8c0 kernel/kexec_core.c:687
kimage_load_normal_segment kernel/kexec_core.c:826 [inline]
kimage_load_segment+0xbfb/0x1200 kernel/kexec_core.c:944
do_kexec_load+0x655/0x810 kernel/kexec.c:155
__do_sys_kexec_load kernel/kexec.c:261 [inline]
__se_sys_kexec_load+0x134/0x160 kernel/kexec.c:242
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 8209 tgid 8208 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:2943
kimage_free_entry kernel/kexec_core.c:555 [inline]
kimage_free+0x475/0x9e0 kernel/kexec_core.c:602
do_kexec_load+0x2d2/0x810 kernel/kexec.c:-1
__do_sys_kexec_load kernel/kexec.c:261 [inline]
__se_sys_kexec_load+0x134/0x160 kernel/kexec.c:242
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88804f9d7e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88804f9d7f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804f9d7f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88804f9d8000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88804f9d8080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
0: 7e 92 jle 0xffffff94
2: 83 b8 2c 0b 00 00 00 cmpl $0x0,0xb2c(%rax)
9: 0f 85 d5 00 00 00 jne 0xe4
f: 48 c7 44 24 30 00 00 movq $0x0,0x30(%rsp)
16: 00 00
18: 9c pushf
19: 8f 44 24 30 pop 0x30(%rsp)
1d: 4c 89 74 24 10 mov %r14,0x10(%rsp)
22: 4d 89 fe mov %r15,%r14
25: 4c 8b 7c 24 30 mov 0x30(%rsp),%r15
* 2a: fa cli <-- trapping instruction
2b: 48 c7 c7 93 5c 7a 8d mov $0xffffffff8d7a5c93,%rdi
32: e8 a2 f6 bc 09 call 0x9bcf6d9
37: 65 ff 05 2b 5d e0 10 incl %gs:0x10e05d2b(%rip) # 0x10e05d69
3e: 45 rex.RB
3f: 31 .byte 0x31