udc dummy_udc.0: failed to start USB Gadget filesystem: -12 gadgetfs gadget.0: probe with driver gadgetfs failed with error -12 udc dummy_udc.1: failed to start USB Gadget filesystem: -12 gadgetfs gadget.1: probe with driver gadgetfs failed with error -12 ================================================================== BUG: KASAN: slab-use-after-free in gadgetfs_bind+0xd8/0xad0 drivers/usb/gadget/legacy/inode.c:1691 Write of size 8 at addr ffff888066b768c0 by task syz.4.549/7707 CPU: 1 UID: 0 PID: 7707 Comm: syz.4.549 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 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 gadgetfs_bind+0xd8/0xad0 drivers/usb/gadget/legacy/inode.c:1691 gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662 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 __driver_attach+0x339/0x600 drivers/base/dd.c:1292 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383 bus_add_driver+0x345/0x670 drivers/base/bus.c:763 driver_register+0x23a/0x320 drivers/base/driver.c:174 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752 dev_config+0xe3c/0x12a0 drivers/usb/gadget/legacy/inode.c:1892 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd0ceb9e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd0cfaae028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd0cee25fa0 RCX: 00007fd0ceb9e0d9 RDX: 000000000000001f RSI: 0000200000000400 RDI: 0000000000000003 RBP: 00007fd0cec35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd0cee26038 R14: 00007fd0cee25fa0 R15: 00007ffe1847e828 Allocated by task 5620: 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] __kmalloc_cache_noprof+0x31d/0x600 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] dev_new drivers/usb/gadget/legacy/inode.c:176 [inline] gadgetfs_fill_super+0x27b/0x790 drivers/usb/gadget/legacy/inode.c:2063 vfs_get_super fs/super.c:1405 [inline] get_tree_single+0xc0/0x150 fs/super.c:1432 vfs_get_tree+0x92/0x2a0 fs/super.c:1947 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3772 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3848 do_mount fs/namespace.c:4181 [inline] __do_sys_mount fs/namespace.c:4397 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4374 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 7707: 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:2748 [inline] slab_free mm/slub.c:6499 [inline] kfree+0x1c5/0x650 mm/slub.c:6792 gadgetfs_bind+0x93c/0xad0 drivers/usb/gadget/legacy/inode.c:1712 gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662 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 __driver_attach+0x339/0x600 drivers/base/dd.c:1292 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383 bus_add_driver+0x345/0x670 drivers/base/bus.c:763 driver_register+0x23a/0x320 drivers/base/driver.c:174 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752 dev_config+0xe3c/0x12a0 drivers/usb/gadget/legacy/inode.c:1892 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888066b76800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 192 bytes inside of freed 1024-byte region [ffff888066b76800, ffff888066b76c00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x66b70 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b003dc0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b003dc0 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 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 5621, tgid 5621 (syz-executor), ts 94999060174 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+0x2205/0x2280 mm/page_alloc.c:4001 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5498 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+0x2d5/0x350 mm/slub.c:7410 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x2c4/0x6b0 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_node_noprof+0x549/0x720 mm/slub.c:5426 _kmalloc_node_noprof include/linux/slab.h:1200 [inline] qdisc_alloc+0x92/0x9d0 net/sched/sch_generic.c:998 qdisc_create_dflt+0x8e/0x4e0 net/sched/sch_generic.c:1053 attach_one_default_qdisc net/sched/sch_generic.c:1219 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2740 [inline] attach_default_qdiscs net/sched/sch_generic.c:1237 [inline] dev_activate+0x37a/0x1150 net/sched/sch_generic.c:1296 __dev_open+0x699/0x850 net/core/dev.c:1711 __dev_change_flags+0x329/0x820 net/core/dev.c:9763 netif_change_flags+0x7c/0x1b0 net/core/dev.c:9828 do_setlink+0xdd6/0x4670 net/core/rtnetlink.c:3246 rtnl_changelink net/core/rtnetlink.c:3885 [inline] __rtnl_newlink net/core/rtnetlink.c:4056 [inline] rtnl_newlink+0x15a3/0x1c30 net/core/rtnetlink.c:4195 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7112 page last free pid 5603 tgid 5603 ts 84654022850 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] free_unref_folios+0xdc2/0x14e0 mm/page_alloc.c:3080 folios_put_refs+0x9e9/0xb30 mm/folio.c:988 free_pages_and_swap_cache+0x2ba/0x490 mm/swap_state.c:591 __tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline] tlb_batch_pages_flush mm/mmu_gather.c:151 [inline] tlb_flush_mmu_free mm/mmu_gather.c:417 [inline] tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:424 tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549 unmap_region+0x2a5/0x330 mm/vma.c:522 vms_clear_ptes mm/vma.c:1370 [inline] vms_complete_munmap_vmas+0x427/0xbe0 mm/vma.c:1412 do_vmi_align_munmap+0x3b7/0x4b0 mm/vma.c:1671 do_vmi_munmap+0x252/0x2d0 mm/vma.c:1719 __vm_munmap+0x241/0x3e0 mm/vma.c:3416 __do_sys_munmap mm/mmap.c:1094 [inline] __se_sys_munmap mm/mmap.c:1091 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1091 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888066b76780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888066b76800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888066b76880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888066b76900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888066b76980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================