================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:814 [inline] BUG: KASAN: use-after-free in enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541 Write of size 8 at addr ffff8881d47031c8 by task syz.7.383/1787 CPU: 1 PID: 1787 Comm: syz.7.383 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack+0x1e/0x20 lib/dump_stack.c:77 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118 print_address_description+0x8d/0x4c0 mm/kasan/report.c:384 __kasan_report+0xef/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137 hlist_add_head include/linux/list.h:814 [inline] enqueue_timer+0x9e/0x2c0 kernel/time/timer.c:541 __internal_add_timer kernel/time/timer.c:554 [inline] internal_add_timer+0x208/0x3e0 kernel/time/timer.c:604 __mod_timer+0x5ab/0x1150 kernel/time/timer.c:1065 mod_timer+0x1f/0x30 kernel/time/timer.c:1117 tun_flow_init drivers/net/tun.c:1446 [inline] tun_net_init+0x2ba/0x580 drivers/net/tun.c:1055 register_netdevice+0x1c4/0x12a0 net/core/dev.c:9139 tun_set_iff+0x812/0xe00 drivers/net/tun.c:2922 __tun_chr_ioctl+0x771/0x18a0 drivers/net/tun.c:3187 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3470 do_vfs_ioctl+0x753/0x13f0 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+0xe1/0x120 fs/ioctl.c:747 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7f586f210969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f586d879038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f586f437fa0 RCX: 00007f586f210969 RDX: 0000200000000280 RSI: 00000000400454ca RDI: 0000000000000003 RBP: 00007f586f292ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f586f437fa0 R15: 00007ffff5145cf8 Allocated by task 523: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x162/0x200 mm/kasan/common.c:529 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:537 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+0x10d/0x2d0 mm/slub.c:4449 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0xdc/0x500 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1080 [inline] nlmsg_new include/net/netlink.h:888 [inline] inet_netconf_notify_devconf+0x169/0x220 net/ipv4/devinet.c:2121 __devinet_sysctl_unregister net/ipv4/devinet.c:2629 [inline] devinet_sysctl_unregister net/ipv4/devinet.c:2653 [inline] inetdev_destroy net/ipv4/devinet.c:326 [inline] inetdev_event+0x7c6/0x1030 net/ipv4/devinet.c:1613 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0xa0/0x120 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] rollback_registered_many+0xa75/0xf40 net/core/dev.c:8650 unregister_netdevice_many+0x4b/0x290 net/core/dev.c:9805 ip_tunnel_delete_nets+0x343/0x390 net/ipv4/ip_tunnel.c:1129 vti_exit_batch_net+0x22/0x30 net/ipv4/ip_vti.c:526 ops_exit_list net/core/net_namespace.c:187 [inline] cleanup_net+0x5fd/0xb40 net/core/net_namespace.c:612 process_one_work+0x73b/0xcc0 kernel/workqueue.c:2290 worker_thread+0xa5c/0x13b0 kernel/workqueue.c:2436 kthread+0x31e/0x3a0 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Freed by task 523: 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+0x1c3/0x280 mm/kasan/common.c:487 kasan_slab_free+0xe/0x10 mm/kasan/common.c:496 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook+0xb7/0x180 mm/slub.c:1494 slab_free mm/slub.c:3080 [inline] kfree+0xbe/0x260 mm/slub.c:4071 skb_free_head net/core/skbuff.c:601 [inline] skb_release_data+0x4ea/0x610 net/core/skbuff.c:621 skb_release_all net/core/skbuff.c:675 [inline] __kfree_skb net/core/skbuff.c:689 [inline] consume_skb+0xad/0x240 net/core/skbuff.c:849 netlink_broadcast_filtered+0x1198/0x1290 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+0xed/0x1b0 net/netlink/af_netlink.c:2510 rtnl_notify+0x9a/0xc0 net/core/rtnetlink.c:737 inet_netconf_notify_devconf+0x1c2/0x220 net/ipv4/devinet.c:2133 __devinet_sysctl_unregister net/ipv4/devinet.c:2629 [inline] devinet_sysctl_unregister net/ipv4/devinet.c:2653 [inline] inetdev_destroy net/ipv4/devinet.c:326 [inline] inetdev_event+0x7c6/0x1030 net/ipv4/devinet.c:1613 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0xa0/0x120 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] rollback_registered_many+0xa75/0xf40 net/core/dev.c:8650 unregister_netdevice_many+0x4b/0x290 net/core/dev.c:9805 ip_tunnel_delete_nets+0x343/0x390 net/ipv4/ip_tunnel.c:1129 vti_exit_batch_net+0x22/0x30 net/ipv4/ip_vti.c:526 ops_exit_list net/core/net_namespace.c:187 [inline] cleanup_net+0x5fd/0xb40 net/core/net_namespace.c:612 process_one_work+0x73b/0xcc0 kernel/workqueue.c:2290 worker_thread+0xa5c/0x13b0 kernel/workqueue.c:2436 kthread+0x31e/0x3a0 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 The buggy address belongs to the object at ffff8881d4703000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 456 bytes inside of 512-byte region [ffff8881d4703000, ffff8881d4703200) The buggy address belongs to the page: page:ffffea000751c000 refcount:1 mapcount:0 mapping:ffff8881f5c02500 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02500 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__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+0x35e/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894 alloc_slab_page+0x3c/0x3b0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x93/0x420 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x29e/0x420 mm/slub.c:2667 __slab_alloc+0x63/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] __kmalloc_track_caller+0x17c/0x2d0 mm/slub.c:4449 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0xdc/0x500 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1080 [inline] nlmsg_new include/net/netlink.h:888 [inline] inet_netconf_notify_devconf+0x169/0x220 net/ipv4/devinet.c:2121 __devinet_sysctl_unregister net/ipv4/devinet.c:2629 [inline] devinet_sysctl_unregister net/ipv4/devinet.c:2653 [inline] inetdev_destroy net/ipv4/devinet.c:326 [inline] inetdev_event+0x7c6/0x1030 net/ipv4/devinet.c:1613 notifier_call_chain kernel/notifier.c:98 [inline] __raw_notifier_call_chain kernel/notifier.c:399 [inline] raw_notifier_call_chain+0xa0/0x120 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] rollback_registered_many+0xa75/0xf40 net/core/dev.c:8650 unregister_netdevice_many+0x4b/0x290 net/core/dev.c:9805 ip_tunnel_delete_nets+0x343/0x390 net/ipv4/ip_tunnel.c:1129 vti_exit_batch_net+0x22/0x30 net/ipv4/ip_vti.c:526 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+0x7e4/0x910 mm/page_alloc.c:1438 free_the_page mm/page_alloc.c:4956 [inline] __free_pages mm/page_alloc.c:4962 [inline] free_pages+0xf9/0x180 mm/page_alloc.c:4970 stack_depot_save+0x492/0x4c0 lib/stackdepot.c:300 save_stack mm/kasan/common.c:72 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x1c3/0x200 mm/kasan/common.c:529 kasan_kmalloc+0xd/0x20 mm/kasan/common.c:543 __kmalloc+0x12a/0x2f0 mm/slub.c:3913 kmalloc_array include/linux/slab.h:618 [inline] kcalloc include/linux/slab.h:629 [inline] old_dev_ioctl net/bridge/br_ioctl.c:169 [inline] br_dev_ioctl+0x64a/0x13b0 net/bridge/br_ioctl.c:388 dev_ifsioc+0x6a1/0xa40 net/core/dev_ioctl.c:311 dev_ioctl+0x5ea/0xb80 net/core/dev_ioctl.c:508 sock_ioctl+0x6a1/0x710 net/socket.c:1112 do_vfs_ioctl+0x753/0x13f0 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+0xe1/0x120 fs/ioctl.c:747 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Memory state around the buggy address: ffff8881d4703080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d4703100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881d4703180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d4703200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881d4703280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================