IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. ================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x107/0x7c40 kernel/locking/lockdep.c:4933 Read of size 8 at addr ffff88807d0b9540 by task syz.0.858/8370 CPU: 1 PID: 8370 Comm: syz.0.858 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 __lock_acquire+0x107/0x7c40 kernel/locking/lockdep.c:4933 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] bt_accept_unlink+0x5f/0x290 net/bluetooth/af_bluetooth.c:262 l2cap_sock_teardown_cb+0x1af/0x380 net/bluetooth/l2cap_sock.c:1668 l2cap_chan_del+0x8e/0x500 net/bluetooth/l2cap_core.c:695 l2cap_conn_del+0x346/0x5d0 net/bluetooth/l2cap_core.c:1833 hci_disconn_cfm include/net/bluetooth/hci_core.h:1813 [inline] hci_conn_hash_flush+0x113/0x290 net/bluetooth/hci_conn.c:2548 hci_dev_close_sync+0x95e/0x1040 net/bluetooth/hci_sync.c:5304 hci_dev_do_close net/bluetooth/hci_core.c:523 [inline] hci_unregister_dev+0x216/0x500 net/bluetooth/hci_core.c:2717 vhci_release+0x7f/0xd0 drivers/bluetooth/hci_vhci.c:565 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9d5/0x2570 kernel/exit.c:887 do_group_exit+0x229/0x2e0 kernel/exit.c:1030 get_signal+0x1259/0x1340 kernel/signal.c:2880 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fde46b9e0d9 Code: Unable to access opcode bytes at 0x7fde46b9e0af. RSP: 002b:00007fde47a50028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: 0000000000000034 RBX: 00007fde46e26180 RCX: 00007fde46b9e0d9 RDX: 0000000000000000 RSI: 0000200000000540 RDI: 0000000000000003 RBP: 00007fde46c35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fde46e26218 R14: 00007fde46e26180 R15: 00007ffff48a80a8 Allocated by task 6223: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc_node_track_caller+0xb0/0x240 mm/slab_common.c:956 kmalloc_reserve net/core/skbuff.c:446 [inline] __alloc_skb+0x226/0x7d0 net/core/skbuff.c:515 alloc_skb include/linux/skbuff.h:1303 [inline] nlmsg_new include/net/netlink.h:998 [inline] rtmsg_ifinfo_build_skb+0x80/0x190 net/core/rtnetlink.c:3980 unregister_netdevice_many_notify+0x1175/0x1990 net/core/dev.c:11027 unregister_netdevice_many net/core/dev.c:11077 [inline] default_device_exit_batch+0x95e/0x9f0 net/core/dev.c:11549 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x78e/0xba0 net/core/net_namespace.c:640 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 6223: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3700 skb_free_head net/core/skbuff.c:762 [inline] skb_release_data+0x5e9/0x7e0 net/core/skbuff.c:791 skb_release_all net/core/skbuff.c:856 [inline] __kfree_skb net/core/skbuff.c:870 [inline] consume_skb+0xa2/0x100 net/core/skbuff.c:1035 netlink_broadcast+0xffd/0x10f0 net/netlink/af_netlink.c:1526 nlmsg_multicast include/net/netlink.h:1078 [inline] nlmsg_notify+0xe3/0x1a0 net/netlink/af_netlink.c:2559 unregister_netdevice_many_notify+0x13f6/0x1990 net/core/dev.c:11044 unregister_netdevice_many net/core/dev.c:11077 [inline] default_device_exit_batch+0x95e/0x9f0 net/core/dev.c:11549 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x78e/0xba0 net/core/net_namespace.c:640 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 call_rcu+0x14f/0x950 kernel/rcu/tree.c:2849 netlink_release+0x157e/0x19b0 net/netlink/af_netlink.c:799 __sock_release net/socket.c:654 [inline] sock_close+0xbf/0x210 net/socket.c:1400 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Second to last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 call_rcu+0x14f/0x950 kernel/rcu/tree.c:2849 netlink_release+0x157e/0x19b0 net/netlink/af_netlink.c:799 __sock_release net/socket.c:654 [inline] sock_close+0xbf/0x210 net/socket.c:1400 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9d5/0x2570 kernel/exit.c:887 do_group_exit+0x229/0x2e0 kernel/exit.c:1030 __do_sys_exit_group kernel/exit.c:1041 [inline] __se_sys_exit_group kernel/exit.c:1039 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1039 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88807d0b9000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1344 bytes inside of 2048-byte region [ffff88807d0b9000, ffff88807d0b9800) The buggy address belongs to the physical page: page:ffffea0001f42e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7d0b8 head:ffffea0001f42e00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888017442000 raw: 0000000000000000 0000000000080008 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4282, tgid 4282 (syz-executor), ts 79203765984, free_ts 65430045374 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560 prep_new_page mm/page_alloc.c:2567 [inline] get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658 alloc_slab_page+0x5d/0x180 mm/slub.c:1799 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2d0 mm/slub.c:1997 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc_node_track_caller+0xa0/0x240 mm/slab_common.c:956 kmalloc_reserve net/core/skbuff.c:446 [inline] pskb_expand_head+0x1c0/0x13a0 net/core/skbuff.c:1849 netlink_trim+0x180/0x220 net/netlink/af_netlink.c:1299 netlink_broadcast+0x66/0x10f0 net/netlink/af_netlink.c:1505 nlmsg_multicast include/net/netlink.h:1078 [inline] nlmsg_notify+0xe3/0x1a0 net/netlink/af_netlink.c:2559 register_netdevice+0x17b4/0x1b80 net/core/dev.c:10290 tun_set_iff+0x82b/0xea0 drivers/net/tun.c:2854 __tun_chr_ioctl+0x770/0x1ed0 drivers/net/tun.c:3117 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1487 [inline] free_pcp_prepare mm/page_alloc.c:1537 [inline] free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509 free_slab mm/slub.c:2036 [inline] discard_slab mm/slub.c:2042 [inline] __unfreeze_partials+0x188/0x1e0 mm/slub.c:2591 put_cpu_partial+0x17c/0x250 mm/slub.c:2667 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc+0x18b/0x2f0 mm/slub.c:3383 vm_area_dup+0x23/0x1a0 kernel/fork.c:468 __split_vma+0xb9/0x4f0 mm/mmap.c:2363 mprotect_fixup+0x5dc/0x840 mm/mprotect.c:623 do_mprotect_pkey+0x7ff/0xba0 mm/mprotect.c:792 __do_sys_mprotect mm/mprotect.c:819 [inline] __se_sys_mprotect mm/mprotect.c:816 [inline] __x64_sys_mprotect+0x7c/0x90 mm/mprotect.c:816 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Memory state around the buggy address: ffff88807d0b9400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807d0b9480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807d0b9500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807d0b9580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807d0b9600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================