================================================================== BUG: KASAN: use-after-free in vlan_dev_get_iflink+0x6d/0x70 net/8021q/vlan_dev.c:766 Read of size 4 at addr ffff8881184ca0d0 by task kworker/u4:5/7657 CPU: 0 PID: 7657 Comm: kworker/u4:5 Not tainted 5.15.184-syzkaller-1080580-g4032a894ccb2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound linkwatch_event 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/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0xf1/0x140 mm/kasan/report.c:444 __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:711 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_run_queue+0x4a9/0x7b0 net/core/link_watch.c:213 linkwatch_event+0x4c/0x60 net/core/link_watch.c:252 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 450: 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:433 [inline] ____kasan_kmalloc mm/kasan/common.c:512 [inline] __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:521 kasan_kmalloc include/linux/kasan.h:227 [inline] __kmalloc+0x13d/0x2c0 mm/slub.c:4431 __kmalloc_node include/linux/slab.h:484 [inline] kmalloc_node include/linux/slab.h:639 [inline] kvmalloc_node+0x242/0x330 mm/util.c:628 kvmalloc include/linux/mm.h:851 [inline] kvzalloc include/linux/mm.h:859 [inline] alloc_netdev_mqs+0x8d/0xc90 net/core/dev.c:10900 rtnl_create_link+0x2ef/0x9d0 net/core/rtnetlink.c:3232 __rtnl_newlink net/core/rtnetlink.c:3514 [inline] rtnl_newlink+0x103f/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:2493 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5668 netlink_unicast_kernel net/netlink/af_netlink.c:1315 [inline] netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1341 netlink_sendmsg+0x86a/0xb70 net/netlink/af_netlink.c:1909 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 10: 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:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1749 slab_free mm/slub.c:3521 [inline] kfree+0xc4/0x270 mm/slub.c:4583 kvfree+0x35/0x40 mm/util.c:664 netdev_freemem+0x3f/0x60 net/core/dev.c:10854 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:10710 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 default_device_exit_batch+0x335/0x390 net/core/dev.c:11684 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x602/0xad0 net/core/net_namespace.c:599 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff8881184ca000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 208 bytes inside of 4096-byte region [ffff8881184ca000, ffff8881184cb000) The buggy address belongs to the page: page:ffffea0004613200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1184c8 head:ffffea0004613200 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 0000000000000000 0000000200000001 ffff888100043380 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 0x1d60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 450, ts 54391994578, free_ts 54369609435 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611 get_page_from_freelist+0x2cc5/0x2d50 mm/page_alloc.c:4485 __alloc_pages+0x18f/0x440 mm/page_alloc.c:5781 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1932 [inline] new_slab+0xa1/0x4d0 mm/slub.c:1995 ___slab_alloc+0x381/0x810 mm/slub.c:3028 __slab_alloc+0x49/0x90 mm/slub.c:3115 slab_alloc_node mm/slub.c:3206 [inline] slab_alloc mm/slub.c:3250 [inline] __kmalloc+0x16a/0x2c0 mm/slub.c:4427 __kmalloc_node include/linux/slab.h:484 [inline] kmalloc_node include/linux/slab.h:639 [inline] kvmalloc_node+0x242/0x330 mm/util.c:628 kvmalloc include/linux/mm.h:851 [inline] kvzalloc include/linux/mm.h:859 [inline] alloc_netdev_mqs+0x8d/0xc90 net/core/dev.c:10900 rtnl_create_link+0x2ef/0x9d0 net/core/rtnetlink.c:3232 __rtnl_newlink net/core/rtnetlink.c:3514 [inline] rtnl_newlink+0x103f/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:2493 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5668 netlink_unicast_kernel net/netlink/af_netlink.c:1315 [inline] netlink_unicast+0x87c/0xa40 net/netlink/af_netlink.c:1341 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1472 [inline] free_pcp_prepare mm/page_alloc.c:1544 [inline] free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534 free_unref_page+0xa2/0x550 mm/page_alloc.c:3616 free_the_page mm/page_alloc.c:805 [inline] __free_pages+0x6c/0x100 mm/page_alloc.c:5857 __free_slab+0xe8/0x1e0 mm/slub.c:2020 free_slab mm/slub.c:2035 [inline] discard_slab mm/slub.c:2041 [inline] __unfreeze_partials+0x160/0x190 mm/slub.c:2527 put_cpu_partial+0xc6/0x120 mm/slub.c:2607 __slab_free+0x1d4/0x290 mm/slub.c:3390 do_slab_free mm/slub.c:3509 [inline] ___cache_free+0x104/0x120 mm/slub.c:3530 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:443 kasan_slab_alloc include/linux/kasan.h:217 [inline] slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550 slab_alloc_node mm/slub.c:3240 [inline] slab_alloc mm/slub.c:3250 [inline] __kmalloc_track_caller+0x11f/0x2c0 mm/slub.c:4949 kvasprintf+0xd4/0x180 lib/kasprintf.c:25 kvasprintf_const+0xf2/0x240 lib/kasprintf.c:49 Memory state around the buggy address: ffff8881184c9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881184ca000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881184ca080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881184ca100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881184ca180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready bridge0: port 1(bridge_slave_0) entered disabled state bridge0: port 2(bridge_slave_1) entered disabled state IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered forwarding state IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered forwarding state IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_virt_wifi: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_vlan: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vlan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vlan1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready