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BUG: KASAN: use-after-free in mcp2221_raw_event+0x106a/0x1240 drivers/hid/hid-mcp2221.c:948
Read of size 1 at addr ffff88804dbfbfff by task ktimers/0/16

CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 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:2130 [inline]
 hid_input_report+0x40f/0x530 drivers/hid/hid-core.c:2157
 hid_irq_in+0x47e/0x6d0 drivers/hid/usbhid/hid-core.c:286
 __usb_hcd_giveback_urb+0x3b4/0x5e0 drivers/usb/core/hcd.c:1661
 dummy_timer+0x89c/0x45a0 drivers/usb/gadget/udc/dummy_hcd.c:1995
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x54f/0xd40 kernel/time/hrtimer.c:1825
 hrtimer_run_softirq+0x1a3/0x2e0 kernel/time/hrtimer.c:1842
 handle_softirqs+0x22f/0x710 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 run_ktimerd+0xcf/0x190 kernel/softirq.c:1043
 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 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:0x4dbfb
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 0000000000000000 dead000000000122 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 9937, tgid 9936 (syz.2.1810), ts 288207164633, free_ts 308120812718
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2487 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2655
 new_slab mm/slub.c:2709 [inline]
 ___slab_alloc+0x8d1/0xdd0 mm/slub.c:3891
 __slab_alloc mm/slub.c:3981 [inline]
 __slab_alloc_node mm/slub.c:4056 [inline]
 slab_alloc_node mm/slub.c:4217 [inline]
 __kmalloc_cache_noprof+0xe6/0x320 mm/slub.c:4391
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 genradix_alloc_node include/linux/generic-radix-tree.h:101 [inline]
 __genradix_ptr_alloc+0x352/0x4a0 lib/generic-radix-tree.c:69
 __genradix_prealloc+0x44/0x90 lib/generic-radix-tree.c:216
 sctp_stream_alloc_out net/sctp/stream.c:104 [inline]
 sctp_stream_init+0x14b/0x440 net/sctp/stream.c:149
 sctp_association_init net/sctp/associola.c:232 [inline]
 sctp_association_new+0x10dd/0x25f0 net/sctp/associola.c:296
 sctp_connect_new_asoc+0x2c5/0x690 net/sctp/socket.c:1092
 __sctp_connect+0x5ba/0xd50 net/sctp/socket.c:1198
 __sctp_setsockopt_connectx net/sctp/socket.c:1337 [inline]
 sctp_getsockopt_connectx3+0x2c7/0x450 net/sctp/socket.c:1422
 sctp_getsockopt+0x98a/0xb60 net/sctp/socket.c:8134
 do_sock_getsockopt+0x36f/0x450 net/socket.c:2405
page last free pid 10474 tgid 10474 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xb59/0xce0 mm/page_alloc.c:2895
 discard_slab mm/slub.c:2753 [inline]
 __put_partials+0x159/0x1a0 mm/slub.c:3218
 __slab_free+0x2b3/0x390 mm/slub.c:4550
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_noprof+0x143/0x310 mm/slub.c:4236
 new_handle fs/jbd2/transaction.c:457 [inline]
 jbd2__journal_start+0x146/0x5b0 fs/jbd2/transaction.c:484
 __ext4_journal_start_sb+0x227/0x5c0 fs/ext4/ext4_jbd2.c:115
 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline]
 ext4_dirty_inode+0x93/0x110 fs/ext4/inode.c:6535
 __mark_inode_dirty+0x2ec/0xe10 fs/fs-writeback.c:2527
 generic_update_time fs/inode.c:2063 [inline]
 inode_update_time fs/inode.c:2076 [inline]
 __file_update_time fs/inode.c:2304 [inline]
 file_update_time+0x412/0x490 fs/inode.c:2334
 ext4_page_mkwrite+0x20f/0x1190 fs/ext4/inode.c:6704
 do_page_mkwrite+0x150/0x310 mm/memory.c:3361
 do_shared_fault mm/memory.c:5649 [inline]
 do_fault mm/memory.c:5711 [inline]
 do_pte_missing mm/memory.c:4234 [inline]
 handle_pte_fault mm/memory.c:6052 [inline]
 __handle_mm_fault mm/memory.c:6195 [inline]
 handle_mm_fault+0x124b/0x3400 mm/memory.c:6364
 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336

Memory state around the buggy address:
 ffff88804dbfbe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804dbfbf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804dbfbf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff88804dbfc000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804dbfc080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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