================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x6d/0x70 net/8021q/vlan_dev.c:757 Read of size 4 at addr ffff888112b32100 by task kworker/u4:3/308 CPU: 1 PID: 308 Comm: kworker/u4:3 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: netns cleanup_net Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x169/0x1d8 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+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 vlan_dev_get_iflink+0x6d/0x70 net/8021q/vlan_dev.c:757 dev_get_iflink+0x70/0xc0 net/core/dev.c:824 default_operstate net/core/link_watch.c:41 [inline] rfc2863_policy+0x124/0x2b0 net/core/link_watch.c:53 linkwatch_do_dev+0x3b/0x140 net/core/link_watch.c:160 linkwatch_forget_dev+0x170/0x180 net/core/link_watch.c:238 netdev_wait_allrefs net/core/dev.c:10215 [inline] netdev_run_todo+0x2bb/0xd20 net/core/dev.c:10331 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x335/0x390 net/core/dev.c:11288 ops_exit_list net/core/net_namespace.c:190 [inline] cleanup_net+0x5fb/0xb70 net/core/net_namespace.c:609 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447 kthread+0x346/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Allocated by task 465: 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+0xda/0x110 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] __kmalloc+0x1a7/0x330 mm/slub.c:4038 __kmalloc_node include/linux/slab.h:421 [inline] kmalloc_node include/linux/slab.h:578 [inline] kvmalloc_node+0x88/0x130 mm/util.c:612 kvmalloc include/linux/mm.h:833 [inline] kvzalloc include/linux/mm.h:841 [inline] alloc_netdev_mqs+0x88/0xc80 net/core/dev.c:10527 rtnl_create_link+0x242/0x930 net/core/rtnetlink.c:3195 __rtnl_newlink net/core/rtnetlink.c:3472 [inline] rtnl_newlink+0x105e/0x1640 net/core/rtnetlink.c:3530 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2503 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] __sys_sendto+0x41d/0x580 net/socket.c:2006 __do_sys_sendto net/socket.c:2018 [inline] __se_sys_sendto net/socket.c:2014 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:2014 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 308: 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 kvfree+0x35/0x40 mm/util.c:647 netdev_freemem+0x3f/0x60 net/core/dev.c:10481 netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1886 device_release+0x96/0x1c0 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+0x18a/0x270 lib/kobject.c:761 netdev_run_todo+0xb99/0xd20 net/core/dev.c:10352 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x335/0x390 net/core/dev.c:11288 ops_exit_list net/core/net_namespace.c:190 [inline] cleanup_net+0x5fb/0xb70 net/core/net_namespace.c:609 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447 kthread+0x346/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the object at ffff888112b32000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 256 bytes inside of 4096-byte region [ffff888112b32000, ffff888112b33000) The buggy address belongs to the page: page:ffffea00044acc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112b30 head:ffffea00044acc00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100042c00 raw: 0000000000000000 0000000000040004 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 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 465, ts 44397335951, free_ts 43822143352 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5370 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+0x2a6/0x450 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+0x1ef/0x320 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] nlmsg_new include/net/netlink.h:953 [inline] rtmsg_ifinfo_build_skb+0x7c/0x180 net/core/rtnetlink.c:3844 rtmsg_ifinfo_event net/core/rtnetlink.c:3880 [inline] rtmsg_ifinfo+0x7a/0x130 net/core/rtnetlink.c:3889 __dev_notify_flags+0xdb/0x500 net/core/dev.c:8568 rtnl_configure_link+0x22e/0x330 net/core/rtnetlink.c:-1 __rtnl_newlink net/core/rtnetlink.c:3490 [inline] rtnl_newlink+0x12d1/0x1640 net/core/rtnetlink.c:3530 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2503 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628 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_pcp_prepare mm/page_alloc.c:1421 [inline] free_unref_page_prepare+0x2b7/0x2d0 mm/page_alloc.c:3336 free_unref_page mm/page_alloc.c:3391 [inline] free_the_page mm/page_alloc.c:5429 [inline] __free_pages+0x14b/0x380 mm/page_alloc.c:5440 __vunmap+0x84d/0x9d0 mm/vmalloc.c:2307 __vfree mm/vmalloc.c:2356 [inline] vfree+0x61/0x90 mm/vmalloc.c:2387 kcov_put kernel/kcov.c:408 [inline] kcov_close+0x2b/0x50 kernel/kcov.c:510 __fput+0x2fb/0x770 fs/file_table.c:281 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa4f/0x2480 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 get_signal+0xf7d/0x12e0 kernel/signal.c:2793 arch_do_signal_or_restart+0xbf/0x10f0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 Memory state around the buggy address: ffff888112b32000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888112b32080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888112b32100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888112b32180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888112b32200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================