==================================================================
BUG: KASAN: use-after-free in kobject_get+0x113/0x120 lib/kobject.c:663
Read of size 1 at addr ffff88811e7e403c by task syz.9.780/3192

CPU: 1 PID: 3192 Comm: syz.9.780 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x10f/0x150 mm/kasan/report.c:444
 __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:3518 [inline]
 device_add+0x2f0/0xe90 drivers/base/core.c:3342
 device_create_groups_vargs drivers/base/core.c:4118 [inline]
 device_create+0x26c/0x300 drivers/base/core.c:4160
 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:642
 configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
 vfs_mkdir+0x38b/0x590 fs/namei.c:4073
 do_mkdirat+0x174/0x4d0 fs/namei.c:4098
 __do_sys_mkdirat fs/namei.c:4113 [inline]
 __se_sys_mkdirat fs/namei.c:4111 [inline]
 __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
 x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9b071a40d9
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:00007f9b05bfd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f9b0742bfa0 RCX: 00007f9b071a40d9
RDX: 00000000000001ff RSI: 0000200000000380 RDI: ffffffffffffff9c
RBP: 00007f9b0723b024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b0742c038 R14: 00007f9b0742bfa0 R15: 00007fff39ff1ac8
 </TASK>

Allocated by task 2634:
 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:433 [inline]
 ____kasan_kmalloc mm/kasan/common.c:512 [inline]
 __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521
 kasan_kmalloc include/linux/kasan.h:227 [inline]
 __kmalloc+0x13d/0x2c0 mm/slub.c:4436
 kmalloc include/linux/slab.h:624 [inline]
 kzalloc include/linux/slab.h:750 [inline]
 __register_sysctl_table+0xeb/0x1240 fs/proc/proc_sysctl.c:1326
 register_net_sysctl+0x21d/0x230 net/sysctl_net.c:169
 neigh_sysctl_register+0x9a9/0xa90 net/core/neighbour.c:3718
 devinet_sysctl_register+0xaf/0x1e0 net/ipv4/devinet.c:2641
 inetdev_init+0x2b2/0x500 net/ipv4/devinet.c:284
 inetdev_event+0x1f4/0x1060 net/ipv4/devinet.c:1544
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2070 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2082 [inline]
 call_netdevice_notifiers+0x119/0x190 net/core/dev.c:2096
 register_netdevice+0x110a/0x1490 net/core/dev.c:10462
 veth_newlink+0x6af/0xe20 drivers/net/veth.c:1683
 __rtnl_newlink net/core/rtnetlink.c:3528 [inline]
 rtnl_newlink+0x137f/0x1900 net/core/rtnetlink.c:3576
 rtnetlink_rcv_msg+0x9fd/0xcb0 net/core/rtnetlink.c:5654
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2516
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5672
 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
 netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1348
 netlink_sendmsg+0x879/0xb80 net/netlink/af_netlink.c:1927
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2063
 __do_sys_sendto net/socket.c:2075 [inline]
 __se_sys_sendto net/socket.c:2071 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2071
 x64_sys_call+0x178/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 20:
 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:365
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1728 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754
 slab_free mm/slub.c:3526 [inline]
 kmem_cache_free_bulk+0x4f2/0x730 mm/slub.c:3669
 kfree_bulk include/linux/slab.h:477 [inline]
 kfree_rcu_work+0x16f/0x870 kernel/rcu/tree.c:3334
 process_one_work+0x6c8/0xbb0 kernel/workqueue.c:2328
 worker_thread+0xaa0/0x1250 kernel/workqueue.c:2475
 kthread+0x3f5/0x4f0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

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+0xb6/0x860 kernel/rcu/tree.c:3648
 drop_sysctl_table+0x2f5/0x430 fs/proc/proc_sysctl.c:1687
 unregister_sysctl_table+0x7a/0x120 fs/proc/proc_sysctl.c:1725
 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:175
 neigh_sysctl_unregister+0x78/0x90 net/core/neighbour.c:3737
 devinet_sysctl_unregister net/ipv4/devinet.c:2656 [inline]
 inetdev_destroy net/ipv4/devinet.c:327 [inline]
 inetdev_event+0x7df/0x1060 net/ipv4/devinet.c:1612
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2070 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2082 [inline]
 call_netdevice_notifiers net/core/dev.c:2096 [inline]
 unregister_netdevice_many+0x103d/0x1a00 net/core/dev.c:11176
 default_device_exit_batch+0x35e/0x3c0 net/core/dev.c:11709
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x605/0xae0 net/core/net_namespace.c:599
 process_one_work+0x6c8/0xbb0 kernel/workqueue.c:2328
 worker_thread+0xaa0/0x1250 kernel/workqueue.c:2475
 kthread+0x3f5/0x4f0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff88811e7e4000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 60 bytes inside of
 1024-byte region [ffff88811e7e4000, ffff88811e7e4400)
The buggy address belongs to the page:
page:ffffea000479f800 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88811e7e0800 pfn:0x11e7e0
head:ffffea000479f800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea000470bc08 ffffea00049c9008 ffff888100043080
raw: ffff88811e7e0800 000000000010000f 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 139, ts 18932426397, free_ts 17960678897
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1937 [inline]
 new_slab+0xa0/0x4d0 mm/slub.c:2000
 ___slab_alloc+0x3ac/0x840 mm/slub.c:3033
 __slab_alloc+0x49/0x90 mm/slub.c:3120
 slab_alloc_node mm/slub.c:3211 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 __kmalloc_track_caller+0x169/0x2c0 mm/slub.c:4954
 kmalloc_reserve net/core/skbuff.c:357 [inline]
 __alloc_skb+0x210/0x730 net/core/skbuff.c:428
 alloc_skb include/linux/skbuff.h:1183 [inline]
 alloc_skb_with_frags+0xa8/0x620 net/core/skbuff.c:6207
 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2542
 unix_dgram_sendmsg+0x6f3/0x19b0 net/unix/af_unix.c:1816
 unix_seqpacket_sendmsg+0x118/0x1e0 net/unix/af_unix.c:2277
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x2a6/0x3a0 net/socket.c:1080
 do_iter_readv_writev+0x477/0x5f0 fs/read_write.c:-1
 do_iter_write+0x207/0x7b0 fs/read_write.c:855
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1474 [inline]
 free_pcp_prepare mm/page_alloc.c:1546 [inline]
 free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536
 free_unref_page+0xae/0x540 mm/page_alloc.c:3618
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5900
 free_nonslab_page+0x86/0xc0 mm/slub.c:3564
 kfree+0x19a/0x270 mm/slub.c:4585
 skb_free_head net/core/skbuff.c:656 [inline]
 skb_release_data+0x7bd/0xa20 net/core/skbuff.c:678
 skb_release_all net/core/skbuff.c:743 [inline]
 __kfree_skb net/core/skbuff.c:757 [inline]
 consume_skb+0xab/0x1f0 net/core/skbuff.c:930
 skb_free_datagram+0x28/0xe0 net/core/datagram.c:325
 netlink_recvmsg+0x5dd/0xe40 net/netlink/af_netlink.c:2006
 ____sys_recvmsg+0x2ca/0x5b0 net/socket.c:-1
 ___sys_recvmsg+0x213/0x5c0 net/socket.c:2697
 __sys_recvmsg net/socket.c:2727 [inline]
 __do_sys_recvmsg net/socket.c:2737 [inline]
 __se_sys_recvmsg net/socket.c:2734 [inline]
 __x64_sys_recvmsg+0x1fe/0x2d0 net/socket.c:2734
 x64_sys_call+0x705/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:48
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88811e7e3f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88811e7e3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88811e7e4000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88811e7e4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811e7e4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 PID: 3192 Comm: syz.9.780 Tainted: G    B             syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:idr_alloc_cyclic+0xa3/0x5f0 lib/idr.c:121
Code: 01 01 01 01 4b 89 44 2e 08 43 c7 44 2e 10 f3 f3 f3 f3 e8 c0 24 fa fe 49 8d 4c 24 14 48 89 4c 24 28 48 c1 e9 03 48 89 4c 24 58 <42> 0f b6 04 29 84 c0 0f 85 39 04 00 00 45 8b 6c 24 14 31 ff 89 de
RSP: 0018:ffffc90000cdf4a0 EFLAGS: 00010203
RAX: ffffffff826f9220 RBX: 0000000000000000 RCX: 0000000000000004
RDX: ffffc90001d4c000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90000cdf5f0 R08: 0000000000000a20 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200019beb0 R12: 0000000000000010
R13: dffffc0000000000 R14: 1ffff9200019bea0 R15: 0000000000000001
FS:  00007f9b05bfd6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9b05bdcd58 CR3: 0000000114bae000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __kernfs_new_node+0x130/0x670 fs/kernfs/dir.c:599
 kernfs_new_node+0x150/0x260 fs/kernfs/dir.c:669
 kernfs_create_dir_ns+0x47/0x130 fs/kernfs/dir.c:1017
 sysfs_create_dir_ns+0x128/0x290 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:89 [inline]
 kobject_add_internal+0x774/0xde0 lib/kobject.c:263
 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:2976 [inline]
 get_device_parent+0x3a6/0x410 drivers/base/core.c:3031
 device_add+0x308/0xe90 drivers/base/core.c:3343
 device_create_groups_vargs drivers/base/core.c:4118 [inline]
 device_create+0x26c/0x300 drivers/base/core.c:4160
 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:642
 configfs_mkdir+0x50a/0x9c0 fs/configfs/dir.c:1329
 vfs_mkdir+0x38b/0x590 fs/namei.c:4073
 do_mkdirat+0x174/0x4d0 fs/namei.c:4098
 __do_sys_mkdirat fs/namei.c:4113 [inline]
 __se_sys_mkdirat fs/namei.c:4111 [inline]
 __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
 x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9b071a40d9
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:00007f9b05bfd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f9b0742bfa0 RCX: 00007f9b071a40d9
RDX: 00000000000001ff RSI: 0000200000000380 RDI: ffffffffffffff9c
RBP: 00007f9b0723b024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b0742c038 R14: 00007f9b0742bfa0 R15: 00007fff39ff1ac8
 </TASK>
Modules linked in:
---[ end trace f2d597f693dede4c ]---
RIP: 0010:idr_alloc_cyclic+0xa3/0x5f0 lib/idr.c:121
Code: 01 01 01 01 4b 89 44 2e 08 43 c7 44 2e 10 f3 f3 f3 f3 e8 c0 24 fa fe 49 8d 4c 24 14 48 89 4c 24 28 48 c1 e9 03 48 89 4c 24 58 <42> 0f b6 04 29 84 c0 0f 85 39 04 00 00 45 8b 6c 24 14 31 ff 89 de
RSP: 0018:ffffc90000cdf4a0 EFLAGS: 00010203
RAX: ffffffff826f9220 RBX: 0000000000000000 RCX: 0000000000000004
RDX: ffffc90001d4c000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90000cdf5f0 R08: 0000000000000a20 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200019beb0 R12: 0000000000000010
R13: dffffc0000000000 R14: 1ffff9200019bea0 R15: 0000000000000001
FS:  00007f9b05bfd6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9b05bdcd58 CR3: 0000000114bae000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	01 01                	add    %eax,(%rcx)
   2:	01 01                	add    %eax,(%rcx)
   4:	4b 89 44 2e 08       	mov    %rax,0x8(%r14,%r13,1)
   9:	43 c7 44 2e 10 f3 f3 	movl   $0xf3f3f3f3,0x10(%r14,%r13,1)
  10:	f3 f3
  12:	e8 c0 24 fa fe       	call   0xfefa24d7
  17:	49 8d 4c 24 14       	lea    0x14(%r12),%rcx
  1c:	48 89 4c 24 28       	mov    %rcx,0x28(%rsp)
  21:	48 c1 e9 03          	shr    $0x3,%rcx
  25:	48 89 4c 24 58       	mov    %rcx,0x58(%rsp)
* 2a:	42 0f b6 04 29       	movzbl (%rcx,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 39 04 00 00    	jne    0x470
  37:	45 8b 6c 24 14       	mov    0x14(%r12),%r13d
  3c:	31 ff                	xor    %edi,%edi
  3e:	89 de                	mov    %ebx,%esi