udc dummy_udc.1: failed to start USB Gadget filesystem: -12 gadgetfs: probe of gadget.1 failed with error -12 ================================================================== BUG: KASAN: slab-use-after-free in gadgetfs_bind+0xd3/0x830 drivers/usb/gadget/legacy/inode.c:1677 Write of size 8 at addr ffff88801c3a78c0 by task syz.4.1185/11901 CPU: 0 PID: 11901 Comm: syz.4.1185 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xa8/0x210 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 gadgetfs_bind+0xd3/0x830 drivers/usb/gadget/legacy/inode.c:1677 gadget_bind_driver+0x2b3/0x770 drivers/usb/gadget/udc/core.c:1651 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x247/0xae0 drivers/base/dd.c:717 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879 driver_probe_device+0x4f/0x420 drivers/base/dd.c:909 __driver_attach+0x444/0x6d0 drivers/base/dd.c:1295 bus_for_each_dev+0x235/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x340/0x630 drivers/base/bus.c:723 driver_register+0x23a/0x310 drivers/base/driver.c:246 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1730 dev_config+0xe49/0x1260 drivers/usb/gadget/legacy/inode.c:1878 vfs_write+0x299/0x9a0 fs/read_write.c:582 ksys_write+0x151/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9df5d9e159 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:00007f9df6c92028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f9df6025fa0 RCX: 00007f9df5d9e159 RDX: 000000000000001f RSI: 0000200000000400 RDI: 0000000000000003 RBP: 00007f9df5e35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9df6026038 R14: 00007f9df6025fa0 R15: 00007ffc4705ee48 Allocated by task 5770: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] dev_new drivers/usb/gadget/legacy/inode.c:170 [inline] gadgetfs_fill_super+0x2ec/0x5f0 drivers/usb/gadget/legacy/inode.c:2048 vfs_get_super fs/super.c:1354 [inline] get_tree_single+0xba/0x140 fs/super.c:1381 vfs_get_tree+0x8c/0x280 fs/super.c:1772 do_new_mount+0x24a/0xa40 fs/namespace.c:3386 do_mount fs/namespace.c:3726 [inline] __do_sys_mount fs/namespace.c:3935 [inline] __se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 11901: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843 gadgetfs_bind+0x6d6/0x830 drivers/usb/gadget/legacy/inode.c:1698 gadget_bind_driver+0x2b3/0x770 drivers/usb/gadget/udc/core.c:1651 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x247/0xae0 drivers/base/dd.c:717 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879 driver_probe_device+0x4f/0x420 drivers/base/dd.c:909 __driver_attach+0x444/0x6d0 drivers/base/dd.c:1295 bus_for_each_dev+0x235/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x340/0x630 drivers/base/bus.c:723 driver_register+0x23a/0x310 drivers/base/driver.c:246 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1730 dev_config+0xe49/0x1260 drivers/usb/gadget/legacy/inode.c:1878 vfs_write+0x299/0x9a0 fs/read_write.c:582 ksys_write+0x151/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88801c3a7800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 192 bytes inside of freed 1024-byte region [ffff88801c3a7800, ffff88801c3a7c00) The buggy address belongs to the physical page: page:ffffea000070e800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c3a0 head:ffffea000070e800 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000840 ffff888017c41dc0 ffffea0001f39800 dead000000000002 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 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 5774, tgid 5774 (syz-executor), ts 80905819180, free_ts 80847840073 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582 prep_new_page mm/page_alloc.c:1589 [inline] get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501 alloc_slab_page+0x5d/0x180 mm/slub.c:1881 allocate_slab mm/slub.c:2028 [inline] new_slab+0x87/0x2d0 mm/slub.c:2081 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3253 __slab_alloc mm/slub.c:3339 [inline] __slab_alloc_node mm/slub.c:3392 [inline] slab_alloc_node mm/slub.c:3485 [inline] __kmem_cache_alloc_node+0x11f/0x250 mm/slub.c:3534 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc_node+0xa6/0x240 mm/slab_common.c:1014 kmalloc_node include/linux/slab.h:620 [inline] kzalloc_node include/linux/slab.h:732 [inline] qdisc_alloc+0x95/0xa40 net/sched/sch_generic.c:951 qdisc_create_dflt+0x63/0x430 net/sched/sch_generic.c:1012 attach_one_default_qdisc net/sched/sch_generic.c:1176 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2524 [inline] attach_default_qdiscs net/sched/sch_generic.c:1194 [inline] dev_activate+0x396/0x1160 net/sched/sch_generic.c:1253 __dev_open+0x347/0x430 net/core/dev.c:1528 __dev_change_flags+0x1e8/0x6a0 net/core/dev.c:8741 dev_change_flags+0x7c/0x1a0 net/core/dev.c:8813 do_setlink+0xb69/0x3f40 net/core/rtnetlink.c:2917 __rtnl_newlink net/core/rtnetlink.c:3715 [inline] rtnl_newlink+0x1848/0x2170 net/core/rtnetlink.c:3762 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1182 [inline] free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459 discard_slab mm/slub.c:2127 [inline] __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667 put_cpu_partial+0x17c/0x250 mm/slub.c:2743 __slab_free+0x319/0x400 mm/slub.c:3700 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519 kmem_cache_zalloc include/linux/slab.h:711 [inline] __kernfs_new_node+0xe5/0x7f0 fs/kernfs/dir.c:624 kernfs_new_node+0x14c/0x260 fs/kernfs/dir.c:700 kernfs_create_link+0xa7/0x200 fs/kernfs/symlink.c:39 sysfs_do_create_link_sd+0x83/0x110 fs/sysfs/symlink.c:44 cfg80211_register_wdev+0x268/0x3a0 net/wireless/core.c:1434 cfg80211_register_netdevice+0x1bb/0x2f0 net/wireless/core.c:1463 Memory state around the buggy address: ffff88801c3a7780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88801c3a7800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88801c3a7880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801c3a7900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801c3a7980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================