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BUG: KASAN: use-after-free in find_endpoint drivers/usb/gadget/udc/dummy_hcd.c:1618 [inline]
BUG: KASAN: use-after-free in dummy_timer+0xd1f/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:1890
Read of size 1 at addr ffff8880326b5d12 by task ktimers/0/16

CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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
 find_endpoint drivers/usb/gadget/udc/dummy_hcd.c:1618 [inline]
 dummy_timer+0xd1f/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:1890
 __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
 __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
 hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
 handle_softirqs+0x1da/0x6d0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 run_ktimerd+0x6a/0x100 kernel/softirq.c:1183
 smpboot_thread_fn+0x565/0xa70 kernel/smpboot.c:160
 kthread+0x38b/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:0x326b5
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 0000000000000000 00000000ffffffff 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 29, tgid 29 (ktimers/1), ts 243434385880
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab+0x7d/0x620 mm/slub.c:3462
 new_slab mm/slub.c:3513 [inline]
 refill_objects+0x2d8/0x350 mm/slub.c:7410
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 kmem_cache_alloc_node_noprof+0x4f1/0x660 mm/slub.c:5068
 kmalloc_reserve net/core/skbuff.c:615 [inline]
 __alloc_skb+0x27a/0x7a0 net/core/skbuff.c:715
 skb_copy+0x19d/0x870 net/core/skbuff.c:2191
 mac80211_hwsim_tx_frame_no_nl+0xfab/0x1760 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2020
 mac80211_hwsim_tx_frame+0x199/0x1f0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2428
 mac80211_hwsim_beacon_tx+0x396/0x820 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2504
 __iterate_interfaces+0x2af/0x5a0 net/mac80211/util.c:775
 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:811
 mac80211_hwsim_beacon+0xb2/0x2b0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2536
 __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
 __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
page last free pid 5592 tgid 5592 ts 274216951180 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 __free_frozen_pages+0xf8e/0x1070 mm/page_alloc.c:2962
 __slab_free+0x250/0x2a0 mm/slub.c:5815
 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:4683 [inline]
 slab_alloc_node mm/slub.c:4996 [inline]
 kmem_cache_alloc_noprof+0x360/0x690 mm/slub.c:5010
 ptlock_alloc+0x20/0x70 mm/memory.c:7659
 ptlock_init include/linux/mm.h:3825 [inline]
 pagetable_pte_ctor include/linux/mm.h:3874 [inline]
 __pte_alloc_one_noprof include/asm-generic/pgalloc.h:79 [inline]
 pte_alloc_one+0x7e/0x380 arch/x86/mm/pgtable.c:18
 __pte_alloc+0x25/0x1a0 mm/memory.c:453
 copy_pte_range mm/memory.c:1273 [inline]
 copy_pmd_range+0x4eff/0x57f0 mm/memory.c:1428
 copy_pud_range mm/memory.c:1465 [inline]
 copy_p4d_range mm/memory.c:1489 [inline]
 copy_page_range+0xb40/0x1170 mm/memory.c:1575
 dup_mmap+0xf83/0x1d80 mm/mmap.c:1819
 dup_mm kernel/fork.c:1543 [inline]
 copy_mm+0x11a/0x480 kernel/fork.c:1595
 copy_process+0x1e7d/0x43f0 kernel/fork.c:2307
 kernel_clone+0x2d2/0x8d0 kernel/fork.c:2766
 __do_sys_clone kernel/fork.c:2908 [inline]
 __se_sys_clone kernel/fork.c:2892 [inline]
 __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2892

Memory state around the buggy address:
 ffff8880326b5c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880326b5c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880326b5d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff8880326b5d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880326b5e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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