================================================================== BUG: KASAN: use-after-free in kobject_get+0x113/0x120 lib/kobject.c:663 Read of size 1 at addr ffff88813451903c by task syz.2.789/3731 CPU: 1 PID: 3731 Comm: syz.2.789 Tainted: G W 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:1382 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: 0033:0x7f71f5a580d9 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:00007f71f4490028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f71f5ce0090 RCX: 00007f71f5a580d9 RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c RBP: 00007f71f5aef024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f71f5ce0128 R14: 00007f71f5ce0090 R15: 00007ffff12bbb28 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 3146: 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] consume_skb+0xab/0x1f0 net/core/skbuff.c:851 netlink_unicast_kernel net/netlink/af_netlink.c:1315 [inline] netlink_unicast+0x874/0xa30 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x949/0xb70 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2377 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2431 __sys_sendmsg net/socket.c:2460 [inline] __do_sys_sendmsg net/socket.c:2469 [inline] __se_sys_sendmsg net/socket.c:2467 [inline] __x64_sys_sendmsg+0x201/0x2d0 net/socket.c:2467 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff888134519000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 60 bytes inside of 1024-byte region [ffff888134519000, ffff888134519400) The buggy address belongs to the page: page:ffffea0004d14600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x134518 head:ffffea0004d14600 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 855, ts 44146063142, free_ts 44108696202 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] kmem_cache_alloc_trace+0x1a8/0x2e0 mm/slub.c:2977 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:667 [inline] ipv6_add_dev+0xd2/0x10b0 net/ipv6/addrconf.c:381 addrconf_notify+0x582/0xea0 net/ipv6/addrconf.c:3577 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+0x119/0x190 net/core/dev.c:2078 register_netdevice+0x100a/0x13a0 net/core/dev.c:10098 register_netdev+0x3e/0x50 net/core/dev.c:10191 ip6_tnl_init_net+0x300/0x3c0 net/ipv6/ip6_tunnel.c:2319 ops_init+0x2c0/0x470 net/core/net_namespace.c:144 setup_net+0x34f/0xae0 net/core/net_namespace.c:345 page last free stack trace: reset_page_owner include/linux/page_owner.h:28 [inline] free_pages_prepare mm/page_alloc.c:1349 [inline] __free_pages_ok+0x80b/0x830 mm/page_alloc.c:1629 free_compound_page+0x73/0x90 mm/page_alloc.c:710 destroy_compound_page include/linux/mm.h:970 [inline] __put_compound_page+0x77/0xb0 mm/swap.c:117 __put_page+0xbd/0xe0 mm/swap.c:133 put_page include/linux/mm.h:1268 [inline] __skb_frag_unref include/linux/skbuff.h:3124 [inline] skb_release_data+0x221/0x690 net/core/skbuff.c:620 skb_release_all net/core/skbuff.c:680 [inline] __kfree_skb+0x50/0x70 net/core/skbuff.c:694 __tcp_close+0x20a/0xde0 net/ipv4/tcp.c:2571 tcp_close+0x29/0x110 net/ipv4/tcp.c:2718 inet_release+0x183/0x200 net/ipv4/af_inet.c:432 __sock_release net/socket.c:597 [inline] sock_close+0xb8/0x200 net/socket.c:1287 __fput+0x2dc/0x730 fs/file_table.c:281 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x127/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 Memory state around the buggy address: ffff888134518f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888134518f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888134519000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888134519080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888134519100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== general protection fault, probably for non-canonical address 0xec67a5c9e92a886c: 0000 [#1] PREEMPT SMP KASAN KASAN: maybe wild-memory-access in range [0x633d4e4f49544360-0x633d4e4f49544367] CPU: 1 PID: 3731 Comm: syz.2.789 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:kobj_child_ns_ops lib/kobject.c:1084 [inline] RIP: 0010:kobj_ns_ops lib/kobject.c:1092 [inline] RIP: 0010:kobject_namespace lib/kobject.c:30 [inline] RIP: 0010:create_dir lib/kobject.c:89 [inline] RIP: 0010:kobject_add_internal+0x5e3/0xde0 lib/kobject.c:263 Code: 4c 89 e7 e8 1f 2d 45 ff 4d 8b 24 24 4d 85 e4 0f 84 db 00 00 00 49 83 c4 20 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 e7 e8 ef 2c 45 ff 49 8b 04 24 48 85 c0 0f RSP: 0018:ffffc9000106f7d8 EFLAGS: 00010206 RAX: 0c67a9c9e92a886c RBX: ffff88810bf2f400 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888134519028 RBP: ffffc9000106f830 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200020deec R12: 633d4e4f49544361 R13: ffff88810bf2f418 R14: ffffffff8681cde0 R15: ffff888134519000 FS: 00007f71f44906c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f065bc76dac CR3: 0000000119975000 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:1382 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: 0033:0x7f71f5a580d9 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:00007f71f4490028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f71f5ce0090 RCX: 00007f71f5a580d9 RDX: 00000000000001ff RSI: 0000200000000100 RDI: ffffffffffffff9c RBP: 00007f71f5aef024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f71f5ce0128 R14: 00007f71f5ce0090 R15: 00007ffff12bbb28 Modules linked in: ---[ end trace dd3fcb1eb4e135ee ]--- RIP: 0010:kobj_child_ns_ops lib/kobject.c:1084 [inline] RIP: 0010:kobj_ns_ops lib/kobject.c:1092 [inline] RIP: 0010:kobject_namespace lib/kobject.c:30 [inline] RIP: 0010:create_dir lib/kobject.c:89 [inline] RIP: 0010:kobject_add_internal+0x5e3/0xde0 lib/kobject.c:263 Code: 4c 89 e7 e8 1f 2d 45 ff 4d 8b 24 24 4d 85 e4 0f 84 db 00 00 00 49 83 c4 20 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 e7 e8 ef 2c 45 ff 49 8b 04 24 48 85 c0 0f RSP: 0018:ffffc9000106f7d8 EFLAGS: 00010206 RAX: 0c67a9c9e92a886c RBX: ffff88810bf2f400 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888134519028 RBP: ffffc9000106f830 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200020deec R12: 633d4e4f49544361 R13: ffff88810bf2f418 R14: ffffffff8681cde0 R15: ffff888134519000 FS: 00007f71f44906c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fea7d1f9990 CR3: 0000000119975000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 4c 89 e7 mov %r12,%rdi 3: e8 1f 2d 45 ff call 0xff452d27 8: 4d 8b 24 24 mov (%r12),%r12 c: 4d 85 e4 test %r12,%r12 f: 0f 84 db 00 00 00 je 0xf0 15: 49 83 c4 20 add $0x20,%r12 19: 4c 89 e0 mov %r12,%rax 1c: 48 c1 e8 03 shr $0x3,%rax 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 27: fc ff df * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 e7 mov %r12,%rdi 33: e8 ef 2c 45 ff call 0xff452d27 38: 49 8b 04 24 mov (%r12),%rax 3c: 48 85 c0 test %rax,%rax 3f: 0f .byte 0xf