================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x70/0x80 net/8021q/vlan_dev.c:780 Read of size 4 at addr ffff88810f2ec100 by task kworker/u4:4/656 CPU: 0 PID: 656 Comm: kworker/u4:4 Tainted: G W 5.10.236-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118 print_address_description+0x81/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x179/0x1c0 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 vlan_dev_get_iflink+0x70/0x80 net/8021q/vlan_dev.c:780 dev_get_iflink+0x6f/0xc0 net/core/dev.c:824 default_operstate net/core/link_watch.c:41 [inline] rfc2863_policy+0x127/0x2b0 net/core/link_watch.c:53 linkwatch_do_dev+0x3c/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+0x2ee/0xdc0 net/core/dev.c:10330 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x38f/0x3f0 net/core/dev.c:11287 ops_exit_list net/core/net_namespace.c:190 [inline] cleanup_net+0x6e9/0xcb0 net/core/net_namespace.c:609 process_one_work+0x6dc/0xbd0 kernel/workqueue.c:2301 worker_thread+0xaea/0x1510 kernel/workqueue.c:2447 kthread+0x34b/0x3d0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Allocated by task 781: 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+0xdb/0x110 mm/kasan/common.c:509 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] __kmalloc+0x1aa/0x330 mm/slub.c:4033 __kmalloc_node include/linux/slab.h:418 [inline] kmalloc_node include/linux/slab.h:575 [inline] kvmalloc_node+0x82/0x130 mm/util.c:612 kvmalloc include/linux/mm.h:822 [inline] kvzalloc include/linux/mm.h:830 [inline] alloc_netdev_mqs+0x8e/0xcd0 net/core/dev.c:10526 rtnl_create_link+0x240/0x950 net/core/rtnetlink.c:3195 __rtnl_newlink net/core/rtnetlink.c:3472 [inline] rtnl_newlink+0x1399/0x2000 net/core/rtnetlink.c:3530 rtnetlink_rcv_msg+0x955/0xc50 net/core/rtnetlink.c:5610 netlink_rcv_skb+0x1cf/0x410 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+0x8df/0xac0 net/netlink/af_netlink.c:1333 netlink_sendmsg+0xa46/0xd00 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] __sys_sendto+0x545/0x700 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 656: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x121/0x160 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+0xc0/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kfree+0xc3/0x270 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+0x95/0x1c0 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+0x178/0x260 lib/kobject.c:761 netdev_run_todo+0xc26/0xdc0 net/core/dev.c:10351 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x38f/0x3f0 net/core/dev.c:11287 ops_exit_list net/core/net_namespace.c:190 [inline] cleanup_net+0x6e9/0xcb0 net/core/net_namespace.c:609 process_one_work+0x6dc/0xbd0 kernel/workqueue.c:2301 worker_thread+0xaea/0x1510 kernel/workqueue.c:2447 kthread+0x34b/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 ffff88810f2ec000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 256 bytes inside of 4096-byte region [ffff88810f2ec000, ffff88810f2ed000) The buggy address belongs to the page: page:ffffea00043cba00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10f2e8 head:ffffea00043cba00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 0000000000000000 0000000100000001 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 95, ts 3699736979, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x166/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5349 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x80/0x400 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x302/0x4b0 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] kmem_cache_alloc_trace+0x1bd/0x2e0 mm/slub.c:2972 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] kobject_uevent_env+0x269/0x700 lib/kobject_uevent.c:539 kobject_synth_uevent+0x4eb/0xae0 lib/kobject_uevent.c:208 store_uevent+0x16/0x30 kernel/module.c:1233 module_attr_store+0x5c/0x80 kernel/params.c:921 sysfs_kf_write+0x123/0x140 fs/sysfs/file.c:139 kernfs_fop_write_iter+0x2c4/0x410 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2058 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0xb4c/0xe70 fs/read_write.c:605 ksys_write+0x199/0x2c0 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __x64_sys_write+0x7b/0x90 fs/read_write.c:667 page_owner free stack trace missing Memory state around the buggy address: ffff88810f2ec000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810f2ec080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88810f2ec100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810f2ec180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810f2ec200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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