================================================================== BUG: KASAN: slab-use-after-free in set_link_state+0xc25/0x1000 drivers/usb/gadget/udc/dummy_hcd.c:511 Read of size 4 at addr ffff888029bb14d8 by task syz.0.964/9520 CPU: 1 UID: 0 PID: 9520 Comm: syz.0.964 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: 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 set_link_state+0xc25/0x1000 drivers/usb/gadget/udc/dummy_hcd.c:511 dummy_pullup+0xbf/0x120 drivers/usb/gadget/udc/dummy_hcd.c:933 usb_gadget_disconnect_locked+0x126/0x480 drivers/usb/gadget/udc/core.c:785 gadget_unbind_driver+0xc2/0x410 drivers/usb/gadget/udc/core.c:1718 device_remove drivers/base/dd.c:616 [inline] __device_release_driver drivers/base/dd.c:1349 [inline] device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372 driver_detach+0x1f3/0x2d0 drivers/base/dd.c:1435 bus_remove_driver+0x229/0x320 drivers/base/bus.c:832 usb_gadget_unregister_driver+0x4e/0x70 drivers/usb/gadget/udc/core.c:1784 raw_release+0xd2/0x260 drivers/usb/gadget/legacy/raw_gadget.c:463 __fput+0x42a/0xa80 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:1009 do_group_exit+0x22d/0x2f0 kernel/exit.c:1152 get_signal+0x121b/0x12c0 kernel/signal.c:3046 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe0b96fde99 Code: Unable to access opcode bytes at 0x7fe0b96fde6f. RSP: 002b:00007fe0b7956028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: 0000000000018ff8 RBX: 00007fe0b9985fa0 RCX: 00007fe0b96fde99 RDX: 0000000000018ff8 RSI: 0000200000019680 RDI: 0000000000000003 RBP: 00007fe0b9793eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe0b9986038 R14: 00007fe0b9985fa0 R15: 00007ffe3ee4c648 Allocated by task 1: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_noprof+0x41a/0x780 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] __usb_create_hcd+0x67/0x900 drivers/usb/core/hcd.c:2566 dummy_hcd_probe+0xf6/0x270 drivers/usb/gadget/udc/dummy_hcd.c:2717 platform_probe+0xf9/0x190 drivers/base/platform.c:1439 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620 device_add+0x7d7/0xb80 drivers/base/core.c:3772 platform_device_add+0x4bd/0x860 drivers/base/platform.c:762 dummy_hcd_init+0x667/0xd00 drivers/usb/gadget/udc/dummy_hcd.c:2873 do_one_initcall+0x250/0x870 init/main.c:1347 do_initcall_level+0x10a/0x1a0 init/main.c:1409 do_initcalls+0x59/0xa0 init/main.c:1425 kernel_init_freeable+0x29d/0x3e0 init/main.c:1658 kernel_init+0x1d/0x1d0 init/main.c:1548 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 9535: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6692 dummy_hcd_remove+0x107/0x130 drivers/usb/gadget/udc/dummy_hcd.c:2762 device_remove drivers/base/dd.c:616 [inline] __device_release_driver drivers/base/dd.c:1349 [inline] device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372 unbind_store+0x1a4/0x1d0 drivers/base/bus.c:244 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 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 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 insert_work+0x3d/0x330 kernel/workqueue.c:2226 __queue_work+0xd1d/0x10f0 kernel/workqueue.c:2401 queue_work_on+0x106/0x1d0 kernel/workqueue.c:2452 usb_rh_urb_dequeue drivers/usb/core/hcd.c:845 [inline] unlink1+0x33d/0x3e0 drivers/usb/core/hcd.c:1580 usb_hcd_flush_endpoint+0x167/0x440 drivers/usb/core/hcd.c:1794 usb_disable_endpoint drivers/usb/core/message.c:1362 [inline] usb_disable_interface+0x279/0x350 drivers/usb/core/message.c:1408 usb_unbind_interface+0x265/0x9f0 drivers/usb/core/driver.c:456 device_remove drivers/base/dd.c:618 [inline] __device_release_driver drivers/base/dd.c:1349 [inline] device_release_driver_internal+0x4f5/0x880 drivers/base/dd.c:1372 bus_remove_device+0x449/0x560 drivers/base/bus.c:664 device_del+0x528/0x8f0 drivers/base/core.c:3961 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1478 usb_disconnect+0x32d/0x990 drivers/usb/core/hub.c:2345 usb_remove_hcd+0x275/0x670 drivers/usb/core/hcd.c:3059 dummy_hcd_remove+0xed/0x130 drivers/usb/gadget/udc/dummy_hcd.c:2761 dummy_hcd_remove+0xed/0x130 drivers/usb/gadget/udc/dummy_hcd.c:2761 device_remove drivers/base/dd.c:616 [inline] __device_release_driver drivers/base/dd.c:1349 [inline] device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372 unbind_store+0x1a4/0x1d0 drivers/base/bus.c:244 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 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 Second to last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 insert_work+0x3d/0x330 kernel/workqueue.c:2226 __queue_work+0xd1d/0x10f0 kernel/workqueue.c:2401 queue_work_on+0x106/0x1d0 kernel/workqueue.c:2452 rh_call_control drivers/usb/core/hcd.c:706 [inline] rh_urb_enqueue drivers/usb/core/hcd.c:817 [inline] usb_hcd_submit_urb+0xa2d/0x1b40 drivers/usb/core/hcd.c:1538 usb_start_wait_urb+0x13f/0x5b0 drivers/usb/core/message.c:62 usb_internal_control_msg drivers/usb/core/message.c:117 [inline] usb_control_msg+0x234/0x3e0 drivers/usb/core/message.c:167 usb_clear_port_feature drivers/usb/core/hub.c:456 [inline] hub_port_reset+0x450/0x1800 drivers/usb/core/hub.c:3107 hub_port_init+0xf48/0x28b0 drivers/usb/core/hub.c:5056 hub_port_connect drivers/usb/core/hub.c:5496 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x24e2/0x4cf0 drivers/usb/core/hub.c:5953 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 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 The buggy address belongs to the object at ffff888029bb1000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1240 bytes inside of freed 2048-byte region [ffff888029bb1000, ffff888029bb1800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888029bb7000 pfn:0x29bb0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000240(workingset|head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000240 ffff88813ffb2000 ffffea000097c610 ffffea0000a54610 raw: ffff888029bb7000 0000000800080007 00000000f5000000 0000000000000000 head: 0080000000000240 ffff88813ffb2000 ffffea000097c610 ffffea0000a54610 head: ffff888029bb7000 0000000800080007 00000000f5000000 0000000000000000 head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 13045605640, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x262a/0x26a0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3380 new_slab mm/slub.c:3426 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x544/0x780 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] platform_device_alloc+0x39/0x260 drivers/base/platform.c:627 dummy_hcd_init+0x2c9/0xd00 drivers/usb/gadget/udc/dummy_hcd.c:2841 do_one_initcall+0x250/0x870 init/main.c:1347 do_initcall_level+0x10a/0x1a0 init/main.c:1409 do_initcalls+0x59/0xa0 init/main.c:1425 kernel_init_freeable+0x29d/0x3e0 init/main.c:1658 kernel_init+0x1d/0x1d0 init/main.c:1548 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page_owner free stack trace missing Memory state around the buggy address: ffff888029bb1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029bb1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888029bb1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888029bb1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029bb1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================