IPv6: ADDRCONF(NETDEV_CHANGE): veth1_virt_wifi: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_virt_wifi: link becomes ready ================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x68/0x70 net/8021q/vlan_dev.c:766 Read of size 4 at addr ffff88807b1360d0 by task kworker/u4:4/1275 CPU: 0 PID: 1275 Comm: kworker/u4:4 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_unbound linkwatch_event Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 vlan_dev_get_iflink+0x68/0x70 net/8021q/vlan_dev.c:766 default_operstate net/core/link_watch.c:41 [inline] rfc2863_policy+0xfd/0x280 net/core/link_watch.c:53 linkwatch_do_dev+0x38/0x160 net/core/link_watch.c:160 __linkwatch_run_queue+0x4a9/0x7b0 net/core/link_watch.c:213 linkwatch_event+0x48/0x50 net/core/link_watch.c:252 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 process_scheduled_works kernel/workqueue.c:2373 [inline] worker_thread+0xdca/0x12a0 kernel/workqueue.c:2459 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 4616: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522 kmalloc_node include/linux/slab.h:627 [inline] kvmalloc_node+0x84/0x130 mm/util.c:619 kvmalloc include/linux/mm.h:816 [inline] kvzalloc include/linux/mm.h:824 [inline] alloc_netdev_mqs+0x84/0xc40 net/core/dev.c:10884 rtnl_create_link+0x2fb/0xa90 net/core/rtnetlink.c:3232 __rtnl_newlink net/core/rtnetlink.c:3514 [inline] rtnl_newlink+0x105e/0x17d0 net/core/rtnetlink.c:3572 rtnetlink_rcv_msg+0x9b9/0xe60 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] __sys_sendto+0x423/0x580 net/socket.c:2063 __do_sys_sendto net/socket.c:2075 [inline] __se_sys_sendto net/socket.c:2071 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2071 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 4361: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 device_release+0x92/0x1c0 drivers/base/core.c:-1 kobject_cleanup lib/kobject.c:713 [inline] kobject_release lib/kobject.c:744 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x21d/0x460 lib/kobject.c:761 netdev_run_todo+0x8d0/0xa40 net/core/dev.c:10702 default_device_exit_batch+0x33b/0x390 net/core/dev.c:11668 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x77b/0xb80 net/core/net_namespace.c:635 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff88807b136000 which belongs to the cache kmalloc-cg-4k of size 4096 The buggy address is located 208 bytes inside of 4096-byte region [ffff88807b136000, ffff88807b137000) The buggy address belongs to the page: page:ffffea0001ec4c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b130 head:ffffea0001ec4c00 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff88802a0e8b81 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff88801684c280 raw: 0000000000000000 0000000000040004 00000001ffffffff ffff88802a0e8b81 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4519, ts 71795384389, free_ts 71781306238 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] __kmalloc_node+0x200/0x3b0 mm/slub.c:4456 kmalloc_node include/linux/slab.h:627 [inline] kvmalloc_node+0x84/0x130 mm/util.c:619 kvmalloc include/linux/mm.h:816 [inline] kvzalloc include/linux/mm.h:824 [inline] alloc_netdev_mqs+0x84/0xc40 net/core/dev.c:10884 vti6_init_net+0x100/0x2c0 net/ipv6/ip6_vti.c:1152 ops_init+0x357/0x600 net/core/net_namespace.c:138 setup_net+0x38d/0x9f0 net/core/net_namespace.c:333 copy_net_ns+0x348/0x5b0 net/core/net_namespace.c:503 create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226 ksys_unshare+0x4bc/0x890 kernel/fork.c:3175 __do_sys_unshare kernel/fork.c:3249 [inline] __se_sys_unshare kernel/fork.c:3247 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3247 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x94/0x280 mm/page_alloc.c:3396 free_slab mm/slub.c:2020 [inline] discard_slab mm/slub.c:2026 [inline] __unfreeze_partials+0x1a5/0x200 mm/slub.c:2512 put_cpu_partial+0x12d/0x190 mm/slub.c:2592 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] __kmalloc_track_caller+0x125/0x330 mm/slub.c:4930 kvasprintf+0xd4/0x180 lib/kasprintf.c:25 kobject_set_name_vargs+0x5d/0x110 lib/kobject.c:297 kobject_add_varg lib/kobject.c:392 [inline] kobject_init_and_add+0xda/0x190 lib/kobject.c:481 netdev_queue_add_kobject net/core/net-sysfs.c:1666 [inline] netdev_queue_update_kobjects+0x19c/0x3e0 net/core/net-sysfs.c:1711 register_queue_kobjects net/core/net-sysfs.c:1772 [inline] netdev_register_kobject+0x265/0x310 net/core/net-sysfs.c:2018 register_netdevice+0x1019/0x16b0 net/core/dev.c:10397 veth_newlink+0x668/0xda0 drivers/net/veth.c:1683 Memory state around the buggy address: ffff88807b135f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807b136000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807b136080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807b136100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807b136180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================