================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline] BUG: KASAN: use-after-free in enqueue_timer+0xb7/0x300 kernel/time/timer.c:541 Write of size 8 at addr ffff8881d72531c8 by task kworker/0:3/382 CPU: 0 PID: 382 Comm: kworker/0:3 Not tainted 5.4.290-syzkaller-00017-g6b07fcd94a6a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 hlist_add_head include/linux/list.h:814 [inline] enqueue_timer+0xb7/0x300 kernel/time/timer.c:541 __internal_add_timer kernel/time/timer.c:554 [inline] internal_add_timer+0x240/0x430 kernel/time/timer.c:604 __mod_timer+0x6f1/0x13e0 kernel/time/timer.c:1065 mod_delayed_work_on+0xff/0x190 kernel/workqueue.c:1736 mod_delayed_work include/linux/workqueue.h:531 [inline] addrconf_mod_dad_work+0x79/0x120 net/ipv6/addrconf.c:326 addrconf_dad_work+0xa80/0x16f0 net/ipv6/addrconf.c:4189 process_one_work+0x765/0xd20 kernel/workqueue.c:2290 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Allocated by task 377: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc_node mm/slub.c:2829 [inline] slab_alloc mm/slub.c:2837 [inline] __kmalloc_track_caller+0x100/0x2b0 mm/slub.c:4449 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0xb4/0x4d0 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1080 [inline] nlmsg_new include/net/netlink.h:888 [inline] inet6_rt_notify+0x2db/0x550 net/ipv6/route.c:5988 fib6_del_route net/ipv6/ip6_fib.c:1893 [inline] fib6_del+0x9a3/0xc20 net/ipv6/ip6_fib.c:1926 fib6_clean_node+0x2ed/0x550 net/ipv6/ip6_fib.c:2088 fib6_walk_continue+0x4c7/0x6e0 net/ipv6/ip6_fib.c:2010 fib6_walk+0x164/0x2b0 net/ipv6/ip6_fib.c:2058 fib6_clean_tree net/ipv6/ip6_fib.c:2138 [inline] __fib6_clean_all net/ipv6/ip6_fib.c:2154 [inline] fib6_clean_all+0x20c/0x2d0 net/ipv6/ip6_fib.c:2165 rt6_sync_down_dev net/ipv6/route.c:4776 [inline] rt6_disable_ip+0x160/0x700 net/ipv6/route.c:4781 addrconf_ifdown+0x191/0x1a90 net/ipv6/addrconf.c:3775 addrconf_notify+0x375/0xe50 net/ipv6/addrconf.c:3698 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0x95/0x110 kernel/notifier.c:406 call_netdevice_notifiers_info net/core/dev.c:1670 [inline] call_netdevice_notifiers_extack net/core/dev.c:1682 [inline] call_netdevice_notifiers net/core/dev.c:1696 [inline] dev_close_many+0x354/0x4f0 net/core/dev.c:1439 rollback_registered_many+0x493/0x1330 net/core/dev.c:8627 unregister_netdevice_many+0x46/0x250 net/core/dev.c:9805 ip_tunnel_delete_nets+0x33b/0x380 net/ipv4/ip_tunnel.c:1129 ops_exit_list net/core/net_namespace.c:187 [inline] cleanup_net+0x6e2/0xc90 net/core/net_namespace.c:612 process_one_work+0x765/0xd20 kernel/workqueue.c:2290 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Freed by task 377: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:345 [inline] __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kfree+0x123/0x370 mm/slub.c:4071 skb_release_all net/core/skbuff.c:675 [inline] __kfree_skb net/core/skbuff.c:689 [inline] consume_skb+0xa5/0x2a0 net/core/skbuff.c:849 netlink_broadcast_filtered+0x115f/0x1280 net/netlink/af_netlink.c:1516 netlink_broadcast net/netlink/af_netlink.c:1538 [inline] nlmsg_multicast include/net/netlink.h:968 [inline] nlmsg_notify+0xf7/0x1b0 net/netlink/af_netlink.c:2510 inet6_rt_notify+0x3c8/0x550 net/ipv6/route.c:6000 fib6_del_route net/ipv6/ip6_fib.c:1893 [inline] fib6_del+0x9a3/0xc20 net/ipv6/ip6_fib.c:1926 fib6_clean_node+0x2ed/0x550 net/ipv6/ip6_fib.c:2088 fib6_walk_continue+0x4c7/0x6e0 net/ipv6/ip6_fib.c:2010 fib6_walk+0x164/0x2b0 net/ipv6/ip6_fib.c:2058 fib6_clean_tree net/ipv6/ip6_fib.c:2138 [inline] __fib6_clean_all net/ipv6/ip6_fib.c:2154 [inline] fib6_clean_all+0x20c/0x2d0 net/ipv6/ip6_fib.c:2165 rt6_sync_down_dev net/ipv6/route.c:4776 [inline] rt6_disable_ip+0x160/0x700 net/ipv6/route.c:4781 addrconf_ifdown+0x191/0x1a90 net/ipv6/addrconf.c:3775 addrconf_notify+0x375/0xe50 net/ipv6/addrconf.c:3698 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0x95/0x110 kernel/notifier.c:406 call_netdevice_notifiers_info net/core/dev.c:1670 [inline] call_netdevice_notifiers_extack net/core/dev.c:1682 [inline] call_netdevice_notifiers net/core/dev.c:1696 [inline] dev_close_many+0x354/0x4f0 net/core/dev.c:1439 rollback_registered_many+0x493/0x1330 net/core/dev.c:8627 unregister_netdevice_many+0x46/0x250 net/core/dev.c:9805 ip_tunnel_delete_nets+0x33b/0x380 net/ipv4/ip_tunnel.c:1129 ops_exit_list net/core/net_namespace.c:187 [inline] cleanup_net+0x6e2/0xc90 net/core/net_namespace.c:612 process_one_work+0x765/0xd20 kernel/workqueue.c:2290 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 The buggy address belongs to the object at ffff8881d7253000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 456 bytes inside of 1024-byte region [ffff8881d7253000, ffff8881d7253400) The buggy address belongs to the page: page:ffffea00075c9400 refcount:1 mapcount:0 mapping:ffff8881f5c02280 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02280 raw: 0000000000000000 0000000000100010 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) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] __kmalloc_track_caller+0x16d/0x2b0 mm/slub.c:4449 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0xb4/0x4d0 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1080 [inline] nlmsg_new include/net/netlink.h:888 [inline] inet6_rt_notify+0x2db/0x550 net/ipv6/route.c:5988 fib6_del_route net/ipv6/ip6_fib.c:1893 [inline] fib6_del+0x9a3/0xc20 net/ipv6/ip6_fib.c:1926 fib6_clean_node+0x2ed/0x550 net/ipv6/ip6_fib.c:2088 fib6_walk_continue+0x4c7/0x6e0 net/ipv6/ip6_fib.c:2010 fib6_walk+0x164/0x2b0 net/ipv6/ip6_fib.c:2058 fib6_clean_tree net/ipv6/ip6_fib.c:2138 [inline] __fib6_clean_all net/ipv6/ip6_fib.c:2154 [inline] fib6_clean_all+0x20c/0x2d0 net/ipv6/ip6_fib.c:2165 rt6_sync_down_dev net/ipv6/route.c:4776 [inline] rt6_disable_ip+0x160/0x700 net/ipv6/route.c:4781 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] __free_pages_ok+0x847/0x950 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4955 [inline] __free_pages+0x91/0x140 mm/page_alloc.c:4961 device_release+0x6b/0x190 drivers/base/core.c:1776 kobject_cleanup lib/kobject.c:716 [inline] kobject_release lib/kobject.c:747 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1e6/0x2f0 lib/kobject.c:764 tun_set_iff+0x870/0xdc0 drivers/net/tun.c:2924 __tun_chr_ioctl+0x8a9/0x1d00 drivers/net/tun.c:3187 do_vfs_ioctl+0x742/0x1720 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:742 [inline] __do_sys_ioctl fs/ioctl.c:749 [inline] __se_sys_ioctl fs/ioctl.c:747 [inline] __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Memory state around the buggy address: ffff8881d7253080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d7253100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881d7253180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d7253200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d7253280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================