================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x6d/0x70 net/8021q/vlan_dev.c:766 Read of size 4 at addr ffff8881161b60d0 by task kworker/u4:2/93 CPU: 1 PID: 93 Comm: kworker/u4:2 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: netns cleanup_net Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106 print_address_description+0x7f/0x2b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xe0/0x130 mm/kasan/report.c:451 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 vlan_dev_get_iflink+0x6d/0x70 net/8021q/vlan_dev.c:766 dev_get_iflink+0x70/0xc0 net/core/dev.c:704 default_operstate net/core/link_watch.c:41 [inline] rfc2863_policy+0x124/0x2b0 net/core/link_watch.c:53 linkwatch_do_dev+0x3b/0x160 net/core/link_watch.c:160 linkwatch_forget_dev+0x170/0x180 net/core/link_watch.c:238 netdev_run_todo+0x2af/0x990 net/core/dev.c:10679 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x335/0x390 net/core/dev.c:11668 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x6d7/0xc20 net/core/net_namespace.c:635 process_one_work+0x6be/0xba0 kernel/workqueue.c:2310 worker_thread+0xa56/0x1200 kernel/workqueue.c:2457 kthread+0x411/0x500 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 551: 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+0xda/0x110 mm/kasan/common.c:513 __kasan_kmalloc+0xd/0x20 mm/kasan/common.c:522 kasan_kmalloc include/linux/kasan.h:264 [inline] __kmalloc+0x139/0x270 mm/slub.c:4412 __kmalloc_node include/linux/slab.h:475 [inline] kmalloc_node include/linux/slab.h:630 [inline] kvmalloc_node+0x88/0x130 mm/util.c:619 kvmalloc include/linux/mm.h:816 [inline] kvzalloc include/linux/mm.h:824 [inline] alloc_netdev_mqs+0x8d/0xc80 net/core/dev.c:10884 rtnl_create_link+0x2ef/0x9d0 net/core/rtnetlink.c:3232 __rtnl_newlink net/core/rtnetlink.c:3514 [inline] rtnl_newlink+0x1041/0x17b0 net/core/rtnetlink.c:3572 rtnetlink_rcv_msg+0x9e4/0xb90 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5668 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x86c/0xb70 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+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 93: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:366 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xc0/0x210 mm/slub.c:4564 kvfree+0x35/0x40 mm/util.c:654 netdev_freemem+0x3f/0x60 net/core/dev.c:10838 netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1903 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+0x812/0x990 net/core/dev.c:10702 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x335/0x390 net/core/dev.c:11668 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x6d7/0xc20 net/core/net_namespace.c:635 process_one_work+0x6be/0xba0 kernel/workqueue.c:2310 worker_thread+0xa56/0x1200 kernel/workqueue.c:2457 kthread+0x411/0x500 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff8881161b6000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 208 bytes inside of 4096-byte region [ffff8881161b6000, ffff8881161b7000) The buggy address belongs to the page: page:ffffea0004586c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1161b0 head:ffffea0004586c00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 0000000000000000 dead000000000122 ffff888100042140 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 551, ts 47212824122, free_ts 46985190922 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x132/0x160 mm/page_alloc.c:2420 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x2fda/0x30b0 mm/page_alloc.c:4192 __alloc_pages+0x246/0x4f0 mm/page_alloc.c:5487 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0x98/0x460 mm/slub.c:1980 ___slab_alloc+0x381/0x810 mm/slub.c:3013 __slab_alloc+0x49/0x90 mm/slub.c:3100 slab_alloc_node mm/slub.c:3191 [inline] slab_alloc mm/slub.c:3233 [inline] __kmalloc_track_caller+0x165/0x270 mm/slub.c:4930 kmalloc_reserve net/core/skbuff.c:356 [inline] __alloc_skb+0x21a/0x740 net/core/skbuff.c:427 alloc_skb include/linux/skbuff.h:1162 [inline] nlmsg_new include/net/netlink.h:953 [inline] rtmsg_ifinfo_build_skb+0x7c/0x190 net/core/rtnetlink.c:3884 rtmsg_ifinfo_event net/core/rtnetlink.c:3920 [inline] rtmsg_ifinfo+0x7a/0x130 net/core/rtnetlink.c:3929 __dev_notify_flags+0xdb/0x500 net/core/dev.c:8887 rtnl_configure_link+0x22e/0x330 net/core/rtnetlink.c:-1 __rtnl_newlink net/core/rtnetlink.c:3532 [inline] rtnl_newlink+0x135a/0x17b0 net/core/rtnetlink.c:3572 rtnetlink_rcv_msg+0x9e4/0xb90 net/core/rtnetlink.c:5650 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5668 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:1413 [inline] free_unref_page_prepare+0x4f6/0x530 mm/page_alloc.c:3317 free_unref_page+0x7d/0x1c0 mm/page_alloc.c:3396 free_the_page mm/page_alloc.c:705 [inline] __free_pages+0x6c/0x100 mm/page_alloc.c:5563 __free_slab+0xe8/0x1e0 mm/slub.c:2005 free_slab mm/slub.c:2020 [inline] discard_slab mm/slub.c:2026 [inline] __unfreeze_partials+0x160/0x190 mm/slub.c:2512 put_cpu_partial+0xc6/0x120 mm/slub.c:2592 __slab_free+0x1d4/0x290 mm/slub.c:3373 do_slab_free mm/slub.c:3492 [inline] ___cache_free+0x104/0x120 mm/slub.c:3511 qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0xf7/0x210 mm/slub.c:3238 vm_area_dup+0x22/0xb0 kernel/fork.c:358 __split_vma+0xb4/0x3a0 mm/mmap.c:2730 Memory state around the buggy address: ffff8881161b5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881161b6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881161b6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881161b6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881161b6180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================