================================================================== BUG: KASAN: use-after-free in kobject_get+0x113/0x120 lib/kobject.c:663 Read of size 1 at addr ffff888111c7a03c by task syz.4.857/3623 CPU: 1 PID: 3623 Comm: syz.4.857 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x100/0x140 mm/kasan/report.c:452 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306 kobject_get+0x113/0x120 lib/kobject.c:663 get_device drivers/base/core.c:3361 [inline] device_add+0x331/0xc00 drivers/base/core.c:3191 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 Allocated by task 84: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] ____kasan_kmalloc mm/kasan/common.c:509 [inline] __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] kmem_cache_alloc_trace+0x179/0x2e0 mm/slub.c:2979 kmalloc include/linux/slab.h:555 [inline] syslog_print+0x127/0x720 kernel/printk/printk.c:1487 do_syslog+0x94c/0x9a0 kernel/printk/printk.c:1644 __do_sys_syslog kernel/printk/printk.c:1736 [inline] __se_sys_syslog kernel/printk/printk.c:1734 [inline] __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1734 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 95: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1600 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626 slab_free mm/slub.c:3208 [inline] kfree+0xc0/0x270 mm/slub.c:4196 skb_free_head net/core/skbuff.c:606 [inline] skb_release_data+0x53b/0x690 net/core/skbuff.c:626 skb_release_all net/core/skbuff.c:680 [inline] __kfree_skb net/core/skbuff.c:694 [inline] kfree_skb_partial+0x6e/0x90 net/core/skbuff.c:5280 tcp_data_queue+0x1b96/0x5350 net/ipv4/tcp_input.c:5105 tcp_rcv_established+0xc46/0x19c0 net/ipv4/tcp_input.c:6006 tcp_v4_do_rcv+0x3e4/0x7c0 net/ipv4/tcp_ipv4.c:1699 tcp_v4_rcv+0x2295/0x2810 net/ipv4/tcp_ipv4.c:2095 ip_protocol_deliver_rcu+0x302/0x650 net/ipv4/ip_input.c:204 ip_local_deliver_finish net/ipv4/ip_input.c:231 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x2dd/0x530 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:461 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:558 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:609 [inline] ip_sublist_rcv+0x75b/0x8b0 net/ipv4/ip_input.c:617 ip_list_rcv+0x3e4/0x430 net/ipv4/ip_input.c:652 __netif_receive_skb_list_ptype net/core/dev.c:5456 [inline] __netif_receive_skb_list_core+0x57e/0x770 net/core/dev.c:5504 __netif_receive_skb_list net/core/dev.c:5556 [inline] netif_receive_skb_list_internal+0x7f8/0xaa0 net/core/dev.c:5666 gro_normal_list net/core/dev.c:5820 [inline] napi_complete_done+0x375/0x780 net/core/dev.c:6569 virtqueue_napi_complete drivers/net/virtio_net.c:357 [inline] virtnet_poll+0x8a6/0xef0 drivers/net/virtio_net.c:1567 napi_poll net/core/dev.c:6885 [inline] net_rx_action+0x48d/0xed0 net/core/dev.c:6955 __do_softirq+0x255/0x563 kernel/softirq.c:309 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 kvfree_call_rcu+0x117/0x670 kernel/rcu/tree.c:3539 drop_sysctl_table+0x2f5/0x430 fs/proc/proc_sysctl.c:1684 unregister_sysctl_table+0x75/0x120 fs/proc/proc_sysctl.c:1722 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:127 neigh_sysctl_unregister+0x78/0x90 net/core/neighbour.c:3732 addrconf_sysctl_unregister net/ipv6/addrconf.c:7121 [inline] addrconf_ifdown+0x1628/0x1890 net/ipv6/addrconf.c:3939 addrconf_notify+0x3bd/0xea0 net/ipv6/addrconf.c:-1 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410 call_netdevice_notifiers_info net/core/dev.c:2052 [inline] call_netdevice_notifiers_extack net/core/dev.c:2064 [inline] call_netdevice_notifiers net/core/dev.c:2078 [inline] unregister_netdevice_many+0x100e/0x19f0 net/core/dev.c:10778 default_device_exit_batch+0x35e/0x3c0 net/core/dev.c:11298 ops_exit_list net/core/net_namespace.c:190 [inline] cleanup_net+0x5fe/0xb80 net/core/net_namespace.c:609 process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301 worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447 kthread+0x324/0x3b0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the object at ffff888111c7a000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 60 bytes inside of 1024-byte region [ffff888111c7a000, ffff888111c7a400) The buggy address belongs to the page: page:ffffea0004471e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111c78 head:ffffea0004471e00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 0000000000000000 0000000100000001 ffff888100042f00 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 106, ts 5225130596, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x176/0x190 mm/page_alloc.c:2462 get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1813 [inline] new_slab+0x84/0x3f0 mm/slub.c:1874 new_slab_objects mm/slub.c:2632 [inline] ___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796 __slab_alloc+0x63/0xa0 mm/slub.c:2836 slab_alloc_node mm/slub.c:2918 [inline] slab_alloc mm/slub.c:2960 [inline] __kmalloc_track_caller+0x1e4/0x310 mm/slub.c:4541 __kmalloc_reserve net/core/skbuff.c:144 [inline] __alloc_skb+0xdc/0x520 net/core/skbuff.c:212 alloc_skb include/linux/skbuff.h:1126 [inline] alloc_uevent_skb+0x85/0x240 lib/kobject_uevent.c:290 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline] kobject_uevent_net_broadcast+0x335/0x5a0 lib/kobject_uevent.c:409 kobject_uevent_env+0x52b/0x700 lib/kobject_uevent.c:608 kobject_synth_uevent+0x452/0x940 lib/kobject_uevent.c:208 uevent_store+0x25/0x60 drivers/base/core.c:2320 dev_attr_store+0x5e/0x80 drivers/base/core.c:2018 sysfs_kf_write+0x129/0x150 fs/sysfs/file.c:139 kernfs_fop_write_iter+0x2bd/0x400 fs/kernfs/file.c:296 page_owner free stack trace missing Memory state around the buggy address: ffff888111c79f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888111c79f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888111c7a000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888111c7a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888111c7a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ kobject: '@(_' (ffff888111c7a000): is not initialized, yet kobject_get() is being called. WARNING: CPU: 0 PID: 3623 at lib/kobject.c:666 kobject_get+0x7c/0x120 lib/kobject.c:664 Modules linked in: CPU: 0 PID: 3623 Comm: syz.4.857 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:kobject_get+0x7c/0x120 lib/kobject.c:664 Code: 0a ff 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 16 31 45 ff 48 8b 33 48 c7 c7 c0 9b 41 85 48 89 da e8 e4 fc 1e 02 <0f> 0b eb 0c e8 db bb 0a ff eb 4c e8 d4 bb 0a ff 4c 8d 73 38 4c 89 RSP: 0018:ffffc90000b57970 EFLAGS: 00010246 RAX: 863d9db89aa6ec00 RBX: ffff888111c7a000 RCX: 0000000000080000 RDX: ffffc90001449000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000b57988 R08: ffff8881f7052fbf R09: 1ffff1103ee0a5f7 R10: dffffc0000000000 R11: ffffed103ee0a5f8 R12: 0000000000000000 R13: ffff888126eb5068 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f313ba126c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b69420000 CR3: 000000011f86d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: get_device drivers/base/core.c:3361 [inline] device_add+0x331/0xc00 drivers/base/core.c:3191 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 ---[ end trace cb6a543c6570a0ec ]--- ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 3623 at lib/refcount.c:25 refcount_warn_saturate+0x104/0x1a0 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 3623 Comm: syz.4.857 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:refcount_warn_saturate+0x104/0x1a0 lib/refcount.c:25 Code: 04 01 48 c7 c7 a0 49 40 85 e8 98 ca 3a 02 0f 0b eb df e8 8f 89 26 ff c6 05 cc 75 82 04 01 48 c7 c7 e0 48 40 85 e8 7c ca 3a 02 <0f> 0b eb c3 e8 73 89 26 ff c6 05 b1 75 82 04 01 48 c7 c7 40 49 40 RSP: 0018:ffffc90000b57950 EFLAGS: 00010246 RAX: 863d9db89aa6ec00 RBX: 0000000000000002 RCX: 0000000000080000 RDX: ffffc90001449000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000b57960 R08: ffff8881f7152fbf R09: 1ffff1103ee2a5f7 R10: dffffc0000000000 R11: ffffed103ee2a5f8 R12: 0000000000000000 R13: ffff888126eb5068 R14: 0000000000000002 R15: 0000000000000000 FS: 00007f313ba126c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b69420000 CR3: 000000011f86d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] kobject_get+0xfb/0x120 lib/kobject.c:667 get_device drivers/base/core.c:3361 [inline] device_add+0x331/0xc00 drivers/base/core.c:3191 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 ---[ end trace cb6a543c6570a0ed ]--- ------------[ cut here ]------------ kobject: '@(_' (ffff888111c7a000): is not initialized, yet kobject_get() is being called. WARNING: CPU: 1 PID: 3623 at lib/kobject.c:666 kobject_get lib/kobject.c:664 [inline] WARNING: CPU: 1 PID: 3623 at lib/kobject.c:666 kobject_add_internal+0x12e/0xde0 lib/kobject.c:248 Modules linked in: CPU: 1 PID: 3623 Comm: syz.4.857 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:kobject_get lib/kobject.c:664 [inline] RIP: 0010:kobject_add_internal+0x12e/0xde0 lib/kobject.c:248 Code: b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 95 18 45 ff 49 8b 34 24 48 c7 c7 c0 9b 41 85 4c 89 e2 e8 62 e4 1e 02 <0f> 0b e9 04 01 00 00 e8 56 a3 0a ff b8 fe ff ff ff e9 b0 09 00 00 RSP: 0018:ffffc90000b577d8 EFLAGS: 00010246 RAX: 863d9db89aa6ec00 RBX: ffff88810f8ea000 RCX: 0000000000080000 RDX: ffffc90001449000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000b57830 R08: ffff8881f7152fbf R09: 1ffff1103ee2a5f7 R10: dffffc0000000000 R11: ffffed103ee2a5f8 R12: ffff888111c7a000 R13: ffff88810f8ea018 R14: 0000000000000000 R15: 1ffff11021f1d400 FS: 00007f313ba126c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b69420000 CR3: 000000011f86d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kobject_add_varg lib/kobject.c:398 [inline] kobject_add+0x165/0x230 lib/kobject.c:450 class_dir_create_and_add drivers/base/core.c:2825 [inline] get_device_parent+0x3a6/0x410 drivers/base/core.c:2880 device_add+0x349/0xc00 drivers/base/core.c:3192 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 ---[ end trace cb6a543c6570a0ee ]--- ------------[ cut here ]------------ refcount_t: saturated; leaking memory. WARNING: CPU: 1 PID: 3623 at lib/refcount.c:22 refcount_warn_saturate+0x158/0x1a0 lib/refcount.c:22 Modules linked in: CPU: 1 PID: 3623 Comm: syz.4.857 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:refcount_warn_saturate+0x158/0x1a0 lib/refcount.c:22 Code: 04 01 48 c7 c7 60 48 40 85 e8 44 ca 3a 02 0f 0b eb 8b e8 3b 89 26 ff c6 05 77 75 82 04 01 48 c7 c7 60 48 40 85 e8 28 ca 3a 02 <0f> 0b e9 6c ff ff ff e8 1c 89 26 ff c6 05 5c 75 82 04 01 48 c7 c7 RSP: 0018:ffffc90000b577b8 EFLAGS: 00010246 RAX: 863d9db89aa6ec00 RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc90001449000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000b577c8 R08: ffffc90000b57147 R09: fffff5200016ae5c R10: dffffc0000000000 R11: fffff5200016ae29 R12: 00000000c0000000 R13: ffff88810f8ea018 R14: 0000000000000001 R15: ffff888111c7a038 FS: 00007f313ba126c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b69420000 CR3: 000000011f86d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] kobject_get lib/kobject.c:667 [inline] kobject_add_internal+0xc44/0xde0 lib/kobject.c:248 kobject_add_varg lib/kobject.c:398 [inline] kobject_add+0x165/0x230 lib/kobject.c:450 class_dir_create_and_add drivers/base/core.c:2825 [inline] get_device_parent+0x3a6/0x410 drivers/base/core.c:2880 device_add+0x349/0xc00 drivers/base/core.c:3192 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 ---[ end trace cb6a543c6570a0ef ]--- ------------[ cut here ]------------ kobject: '@(_' (ffff888111c7a000): is not initialized, yet kobject_put() is being called. WARNING: CPU: 1 PID: 3623 at lib/kobject.c:760 kobject_put+0x8a/0x270 lib/kobject.c:758 Modules linked in: CPU: 1 PID: 3623 Comm: syz.4.857 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:kobject_put+0x8a/0x270 lib/kobject.c:758 Code: 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 e8 2f 45 ff 48 8b 33 48 c7 c7 40 9c 41 85 48 89 da e8 b6 fb 1e 02 <0f> 0b eb 0f e8 ad ba 0a ff e9 7c 01 00 00 e8 a3 ba 0a ff 4c 8d 7b RSP: 0018:ffffc90000b577a0 EFLAGS: 00010246 RAX: 863d9db89aa6ec00 RBX: ffff888111c7a000 RCX: 0000000000080000 RDX: ffffc90001449000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000b577c8 R08: ffffc90000b57127 R09: fffff5200016ae58 R10: dffffc0000000000 R11: fffff5200016ae25 R12: ffff888111c7a000 R13: ffff888111c7a03c R14: 1ffff1102238f407 R15: 0000000000000000 FS: 00007f313ba126c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b68ffddb8 CR3: 000000011f86d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kobject_add_internal+0xb52/0xde0 lib/kobject.c:266 kobject_add_varg lib/kobject.c:398 [inline] kobject_add+0x165/0x230 lib/kobject.c:450 class_dir_create_and_add drivers/base/core.c:2825 [inline] get_device_parent+0x3a6/0x410 drivers/base/core.c:2880 device_add+0x349/0xc00 drivers/base/core.c:3192 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 ---[ end trace cb6a543c6570a0f0 ]--- ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 3623 at lib/refcount.c:28 refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28 Modules linked in: CPU: 1 PID: 3623 Comm: syz.4.857 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:refcount_warn_saturate+0x120/0x1a0 lib/refcount.c:28 Code: 04 01 48 c7 c7 e0 48 40 85 e8 7c ca 3a 02 0f 0b eb c3 e8 73 89 26 ff c6 05 b1 75 82 04 01 48 c7 c7 40 49 40 85 e8 60 ca 3a 02 <0f> 0b eb a7 e8 57 89 26 ff c6 05 92 75 82 04 01 48 c7 c7 60 48 40 RSP: 0018:ffffc90000b57780 EFLAGS: 00010246 RAX: 863d9db89aa6ec00 RBX: 0000000000000003 RCX: 0000000000080000 RDX: ffffc90001449000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000b57790 R08: ffff8881f7152fbf R09: 1ffff1103ee2a5f7 R10: dffffc0000000000 R11: ffffed103ee2a5f8 R12: 00000000c0000000 R13: ffff888111c7a03c R14: 0000000000000003 R15: ffff888111c7a038 FS: 00007f313ba126c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b68ffddb8 CR3: 000000011f86d000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] kref_put include/linux/kref.h:64 [inline] kobject_put+0x231/0x270 lib/kobject.c:761 kobject_add_internal+0xb52/0xde0 lib/kobject.c:266 kobject_add_varg lib/kobject.c:398 [inline] kobject_add+0x165/0x230 lib/kobject.c:450 class_dir_create_and_add drivers/base/core.c:2825 [inline] get_device_parent+0x3a6/0x410 drivers/base/core.c:2880 device_add+0x349/0xc00 drivers/base/core.c:3192 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 ---[ end trace cb6a543c6570a0f1 ]--- kobject_add_internal failed for android_usb (error: -2 parent: @(_) ------------[ cut here ]------------ kobject: '@(_' (ffff888111c7a000): is not initialized, yet kobject_put() is being called. WARNING: CPU: 0 PID: 3623 at lib/kobject.c:760 kobject_put+0x8a/0x270 lib/kobject.c:758 Modules linked in: CPU: 0 PID: 3623 Comm: syz.4.857 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:kobject_put+0x8a/0x270 lib/kobject.c:758 Code: 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 e8 2f 45 ff 48 8b 33 48 c7 c7 40 9c 41 85 48 89 da e8 b6 fb 1e 02 <0f> 0b eb 0f e8 ad ba 0a ff e9 7c 01 00 00 e8 a3 ba 0a ff 4c 8d 7b RSP: 0018:ffffc90000b57960 EFLAGS: 00010246 RAX: 863d9db89aa6ec00 RBX: ffff888111c7a000 RCX: 0000000000080000 RDX: ffffc90001449000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000b57988 R08: ffffc90000b572e7 R09: fffff5200016ae90 R10: dffffc0000000000 R11: fffff5200016ae5d R12: fffffffffffffffe R13: ffff888111c7a03c R14: 1ffff1102238f407 R15: 0000000000000000 FS: 00007f313ba126c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1107e72f8 CR3: 000000011f86d000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: put_device drivers/base/core.c:3373 [inline] device_add+0x36f/0xc00 drivers/base/core.c:3318 device_create_groups_vargs drivers/base/core.c:3960 [inline] device_create+0x26c/0x300 drivers/base/core.c:4002 create_function_device+0x60/0x70 drivers/usb/gadget/configfs.c:31 create_alsa_device drivers/usb/gadget/function/f_midi.c:1262 [inline] f_midi_alloc_inst+0x1a8/0x380 drivers/usb/gadget/function/f_midi.c:1303 try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline] usb_get_function_instance+0xe2/0x2f0 drivers/usb/gadget/functions.c:44 function_make+0x118/0x350 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x5d2/0xd90 fs/configfs/dir.c:1354 vfs_mkdir+0x42c/0x600 fs/namei.c:3798 do_mkdirat+0x14c/0x340 fs/namei.c:3820 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f313cfb9019 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:00007f313ba12028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f313d240fa0 RCX: 00007f313cfb9019 RDX: 00000000000001ff RSI: 00002000000003c0 RDI: ffffffffffffff9c RBP: 00007f313d05000c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f313d241038 R14: 00007f313d240fa0 R15: 00007ffe28485538 ---[ end trace cb6a543c6570a0f2 ]---