================================================================== BUG: KASAN: use-after-free in rcu_segcblist_enqueue+0x85/0xa0 kernel/rcu/rcu_segcblist.c:250 Write of size 8 at addr ffff888106bf4590 by task syz.5.212/1184 CPU: 0 PID: 1184 Comm: syz.5.212 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x1a7/0x208 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+0x100/0x140 mm/kasan/report.c:452 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report_generic.c:314 rcu_segcblist_enqueue+0x85/0xa0 kernel/rcu/rcu_segcblist.c:250 __call_rcu kernel/rcu/tree.c:2998 [inline] call_rcu+0x4df/0x1090 kernel/rcu/tree.c:3054 security_inode_free+0xb4/0xd0 security/security.c:984 __destroy_inode+0x175/0x4f0 fs/inode.c:258 destroy_inode fs/inode.c:281 [inline] evict+0x7e8/0x940 fs/inode.c:629 iput_final fs/inode.c:1736 [inline] iput+0x654/0x7e0 fs/inode.c:1762 dentry_unlink_inode+0x2d5/0x390 fs/dcache.c:378 __dentry_kill+0x45b/0x660 fs/dcache.c:583 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:883 __fput+0x4bd/0x730 fs/file_table.c:294 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x127/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f8713aabe99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffceaf62aa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007ffceaf62b90 RCX: 00007f8713aabe99 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000000d16d R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b33920000 R11: 0000000000000246 R12: 00007ffceaf62bd0 R13: 00007f8713d33fac R14: 000000000000e14d R15: 00007f8713d33fa0 Allocated by task 1185: 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+0xd4/0x100 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] __kmalloc+0x19f/0x330 mm/slub.c:4038 kmalloc include/linux/slab.h:560 [inline] kzalloc include/linux/slab.h:667 [inline] l2tp_session_create+0x39/0xb60 net/l2tp/l2tp_core.c:1616 pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:772 __sys_connect_file net/socket.c:1867 [inline] __sys_connect+0x3ce/0x450 net/socket.c:1884 __do_sys_connect net/socket.c:1894 [inline] __se_sys_connect net/socket.c:1891 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:1891 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 530: 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:1600 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626 slab_free mm/slub.c:3208 [inline] kfree+0xc0/0x270 mm/slub.c:4196 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline] l2tp_session_put+0xb2/0x1a0 net/l2tp/l2tp_core.c:193 l2tp_session_delete+0x3a9/0x4a0 net/l2tp/l2tp_core.c:1589 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1235 [inline] l2tp_tunnel_del_work+0x180/0x3d0 net/l2tp/l2tp_core.c:1273 process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301 worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447 kthread+0x324/0x3b0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2980 [inline] call_rcu+0x11a/0x1090 kernel/rcu/tree.c:3054 pppol2tp_release+0x1e3/0x2b0 net/l2tp/l2tp_ppp.c:447 __sock_release net/socket.c:597 [inline] sock_close+0xb8/0x200 net/socket.c:1287 __fput+0x2dc/0x730 fs/file_table.c:281 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x127/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xcb/0xe0 kernel/entry/common.c:172 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb Second to last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2980 [inline] call_rcu+0x11a/0x1090 kernel/rcu/tree.c:3054 fib6_info_release include/net/ip6_fib.h:346 [inline] ip6_route_info_create+0xa44/0x1450 net/ipv6/route.c:3753 ip6_route_add+0x27/0x130 net/ipv6/route.c:3767 addrconf_prefix_route+0x233/0x310 net/ipv6/addrconf.c:2462 inet6_addr_add+0x51d/0x970 net/ipv6/addrconf.c:3019 inet6_rtm_newaddr+0x6e1/0x9c0 net/ipv6/addrconf.c:4960 rtnetlink_rcv_msg+0x9e9/0xca0 net/core/rtnetlink.c:5614 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2508 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5632 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x949/0xb70 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] __sys_sendto+0x467/0x620 net/socket.c:2007 __do_sys_sendto net/socket.c:2019 [inline] __se_sys_sendto net/socket.c:2015 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:2015 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff888106bf4400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 400 bytes inside of 512-byte region [ffff888106bf4400, ffff888106bf4600) The buggy address belongs to the page: page:ffffea00041afd00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106bf4 head:ffffea00041afd00 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 ffffea00049ae400 0000000500000005 ffff888100043080 raw: 0000000000000000 0000000000100010 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 282, ts 23149123495, free_ts 23121434954 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x176/0x190 mm/page_alloc.c:2462 get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1813 [inline] new_slab+0x84/0x3f0 mm/slub.c:1874 new_slab_objects mm/slub.c:2632 [inline] ___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796 __slab_alloc+0x63/0xa0 mm/slub.c:2836 slab_alloc_node mm/slub.c:2918 [inline] slab_alloc mm/slub.c:2960 [inline] kmem_cache_alloc_trace+0x1a8/0x2e0 mm/slub.c:2977 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:667 [inline] ipv6_add_addr+0x408/0xd90 net/ipv6/addrconf.c:1113 inet6_addr_add+0x453/0x970 net/ipv6/addrconf.c:3016 inet6_rtm_newaddr+0x6e1/0x9c0 net/ipv6/addrconf.c:4960 rtnetlink_rcv_msg+0x9e9/0xca0 net/core/rtnetlink.c:5614 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2508 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5632 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x949/0xb70 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] __sys_sendto+0x467/0x620 net/socket.c:2007 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+0x80b/0x830 mm/page_alloc.c:1629 free_the_page mm/page_alloc.c:5445 [inline] __free_pages+0xd8/0x390 mm/page_alloc.c:5454 __free_slab+0xcf/0x190 mm/slub.c:1899 free_slab mm/slub.c:1914 [inline] discard_slab mm/slub.c:1920 [inline] unfreeze_partials+0x150/0x180 mm/slub.c:2415 put_cpu_partial+0xc1/0x180 mm/slub.c:2451 __slab_free+0x2c9/0x3a0 mm/slub.c:3100 do_slab_free mm/slub.c:3196 [inline] ___cache_free+0x10e/0x130 mm/slub.c:3215 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/0xe0 mm/kasan/common.c:440 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580 slab_alloc_node mm/slub.c:2952 [inline] slab_alloc mm/slub.c:2960 [inline] kmem_cache_alloc_trace+0x155/0x2e0 mm/slub.c:2977 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:667 [inline] kset_create lib/kobject.c:982 [inline] kset_create_and_add+0x59/0x2c0 lib/kobject.c:1025 register_queue_kobjects net/core/net-sysfs.c:1742 [inline] netdev_register_kobject+0x1be/0x330 net/core/net-sysfs.c:2001 register_netdevice+0xdae/0x13a0 net/core/dev.c:10067 Memory state around the buggy address: ffff888106bf4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888106bf4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888106bf4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888106bf4600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888106bf4680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================