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BUG: KASAN: use-after-free in mcp2221_raw_event+0x103c/0x10a0 drivers/hid/hid-mcp2221.c:948
Read of size 1 at addr ffff888115d3bfff by task ksoftirqd/0/14

CPU: 0 UID: 0 PID: 14 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __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
 run_ksoftirqd kernel/softirq.c:1063 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055
 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x6c3/0xcb0 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:0xffff888115d3b000 pfn:0x115d3b
flags: 0x200000000000000(node=0|zone=2)
page_type: f0(buddy)
raw: 0200000000000000 ffffea0004873f88 ffffea00048b0748 0000000000000000
raw: ffff888115d3b000 0000000000000000 00000000f0000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2855, tgid 2855 (udevd), ts 1087452462037, free_ts 1176094663472
 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_slab_page mm/slub.c:3255 [inline]
 allocate_slab mm/slub.c:3444 [inline]
 new_slab+0xa6/0x6e0 mm/slub.c:3502
 refill_objects+0x26b/0x400 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 alloc_full_sheaf mm/slub.c:2825 [inline]
 __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4588
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 kmem_cache_alloc_noprof+0x520/0x6a0 mm/slub.c:4837
 alloc_filename fs/namei.c:142 [inline]
 do_getname+0x35/0x390 fs/namei.c:182
 getname_flags fs/namei.c:225 [inline]
 getname include/linux/fs.h:2512 [inline]
 class_filename_constructor include/linux/fs.h:2539 [inline]
 __do_sys_unlink fs/namei.c:5574 [inline]
 __se_sys_unlink fs/namei.c:5572 [inline]
 __x64_sys_unlink+0x36/0x70 fs/namei.c:5572
 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
page last free pid 2855 tgid 2855 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
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x4e/0x70 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_noprof+0x2e7/0x6a0 mm/slub.c:4837
 alloc_filename fs/namei.c:142 [inline]
 do_getname+0x35/0x390 fs/namei.c:182
 getname_flags fs/namei.c:225 [inline]
 getname include/linux/fs.h:2512 [inline]
 class_filename_constructor include/linux/fs.h:2539 [inline]
 __do_sys_unlink fs/namei.c:5574 [inline]
 __se_sys_unlink fs/namei.c:5572 [inline]
 __x64_sys_unlink+0x36/0x70 fs/namei.c:5572
 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

Memory state around the buggy address:
 ffff888115d3be80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888115d3bf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888115d3bf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff888115d3c000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888115d3c080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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