================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x6d/0x70 net/8021q/vlan_dev.c:780 Read of size 4 at addr ffff888115a7c100 by task kworker/u4:2/49 CPU: 1 PID: 49 Comm: kworker/u4:2 Tainted: G W 5.10.236-syzkaller-00012-gab07aeb2c93d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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:780 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:10214 [inline] netdev_run_todo+0x2bb/0xd20 net/core/dev.c:10330 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x335/0x390 net/core/dev.c:11287 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 3753: 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:4033 __kmalloc_node include/linux/slab.h:418 [inline] kmalloc_node include/linux/slab.h:575 [inline] kvmalloc_node+0x88/0x130 mm/util.c:612 kvmalloc include/linux/mm.h:822 [inline] kvzalloc include/linux/mm.h:830 [inline] alloc_netdev_mqs+0x88/0xc80 net/core/dev.c:10526 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:2485 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline] netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1333 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1901 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 49: 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:1595 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kfree+0xc0/0x270 mm/slub.c:4191 kvfree+0x35/0x40 mm/util.c:647 netdev_freemem+0x3f/0x60 net/core/dev.c:10480 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:10351 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x335/0x390 net/core/dev.c:11287 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 ffff888115a7c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 256 bytes inside of 4096-byte region [ffff888115a7c000, ffff888115a7d000) The buggy address belongs to the page: page:ffffea0004569e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888115a7a000 pfn:0x115a78 head:ffffea0004569e00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 ffffea0004652608 ffffea000464fc08 ffff888100042c00 raw: ffff888115a7a000 0000000000040002 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 1737, ts 79009275770, free_ts 78999921536 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:5349 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x84/0x3f0 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] __kmalloc_track_caller+0x1ef/0x320 mm/slub.c:4536 __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:8567 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:2485 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_pages_ok+0x7fc/0x820 mm/page_alloc.c:1629 free_the_page mm/page_alloc.c:5410 [inline] __free_pages+0xdd/0x380 mm/page_alloc.c:5419 __free_slab+0xcf/0x190 mm/slub.c:1894 free_slab mm/slub.c:1909 [inline] discard_slab mm/slub.c:1915 [inline] unfreeze_partials+0x15f/0x190 mm/slub.c:2410 put_cpu_partial+0xc1/0x180 mm/slub.c:2446 __slab_free+0x2c9/0x3a0 mm/slub.c:3095 do_slab_free mm/slub.c:3191 [inline] ___cache_free+0x111/0x130 mm/slub.c:3210 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:440 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:583 slab_alloc_node mm/slub.c:2947 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2960 kmem_cache_alloc_node include/linux/slab.h:423 [inline] __alloc_skb+0x9e/0x520 net/core/skbuff.c:200 alloc_skb include/linux/skbuff.h:1126 [inline] nlmsg_new include/net/netlink.h:953 [inline] netlink_ack+0x3a6/0xb80 net/netlink/af_netlink.c:2420 netlink_rcv_skb+0x265/0x430 net/netlink/af_netlink.c:2491 Memory state around the buggy address: ffff888115a7c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888115a7c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888115a7c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888115a7c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888115a7c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================