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BUG: KASAN: use-after-free in mcp2221_raw_event+0x10b0/0x12a0 drivers/hid/hid-mcp2221.c:964
Read of size 1 at addr ffff8880600bbfff by task ktimers/1/29

CPU: 1 UID: 0 PID: 29 Comm: ktimers/1 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 mcp2221_raw_event+0x10b0/0x12a0 drivers/hid/hid-mcp2221.c:964
 __hid_input_report+0x42b/0x590 drivers/hid/hid-core.c:2161
 hid_irq_in+0x495/0x710 drivers/hid/usbhid/hid-core.c:286
 __usb_hcd_giveback_urb+0x3b3/0x5e0 drivers/usb/core/hcd.c:1655
 dummy_timer+0x8a9/0x47d0 drivers/usb/gadget/udc/dummy_hcd.c:2005
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x405/0xb10 kernel/time/hrtimer.c:1994
 hrtimer_run_softirq+0x18f/0x260 kernel/time/hrtimer.c:2011
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1151
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x600bb
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 0000000000000000 ffffea0001802ec8 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 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6593, tgid 6592 (syz.2.234), ts 197713659605, free_ts 226109157403
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x28b2/0x2930 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_noprof+0x530/0x7b0 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 io_cache_alloc_new+0x40/0x100 io_uring/alloc_cache.c:40
 io_cache_alloc io_uring/alloc_cache.h:61 [inline]
 io_uring_alloc_async_data io_uring/io_uring.h:354 [inline]
 io_msg_alloc_async+0x212/0x380 io_uring/net.c:191
 io_bind_prep+0x15d/0x390 io_uring/net.c:1833
 io_init_req io_uring/io_uring.c:1846 [inline]
 io_submit_sqe io_uring/io_uring.c:1893 [inline]
 io_submit_sqes+0xbd3/0x22e0 io_uring/io_uring.c:2061
 __do_sys_io_uring_enter io_uring/io_uring.c:2651 [inline]
 __se_sys_io_uring_enter+0x34a/0x1c40 io_uring/io_uring.c:2600
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6795 tgid 6792 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xfe5/0x10d0 mm/page_alloc.c:2938
 __slab_free+0x252/0x2a0 mm/slub.c:5613
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_node_noprof+0x22a/0x6e0 mm/slub.c:4951
 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
 alloc_skb include/linux/skbuff.h:1385 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 inet_ifmcaddr_notify+0x7e/0x150 net/ipv4/igmp.c:1495
 __ip_mc_dec_group+0x414/0x620 net/ipv4/igmp.c:1792
 inetdev_event+0x2b1/0x1610 net/ipv4/devinet.c:1641
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 __dev_notify_flags+0x16d/0x310 net/core/dev.c:9799
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9826
 do_setlink+0xfa5/0x45a0 net/core/rtnetlink.c:3181
 rtnl_group_changelink net/core/rtnetlink.c:3814 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3982 [inline]
 rtnl_newlink+0x14ca/0x1bb0 net/core/rtnetlink.c:4110
 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6997

Memory state around the buggy address:
 ffff8880600bbe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880600bbf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880600bbf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff8880600bc000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880600bc080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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