================================================================== BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline] BUG: KASAN: use-after-free in test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:70 [inline] BUG: KASAN: use-after-free in l2tp_session_delete+0x24/0x4e0 net/l2tp/l2tp_core.c:1563 Write of size 8 at addr ffff88810f0e7c08 by task kworker/u4:7/7629 CPU: 0 PID: 7629 Comm: kworker/u4:7 Not tainted 5.10.226-syzkaller-00709-ge5e5644ea27f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: l2tp l2tp_tunnel_del_work 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 kasan_check_range+0x293/0x2a0 mm/kasan/generic.c:189 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37 instrument_atomic_read_write include/linux/instrumented.h:101 [inline] test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:70 [inline] l2tp_session_delete+0x24/0x4e0 net/l2tp/l2tp_core.c:1563 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1218 [inline] l2tp_tunnel_del_work+0x19d/0x380 net/l2tp/l2tp_core.c:1258 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 13021: 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 include/linux/slab.h:557 [inline] kzalloc include/linux/slab.h:664 [inline] l2tp_session_create+0x38/0xb60 net/l2tp/l2tp_core.c:1599 pppol2tp_connect+0xc5d/0x1690 net/l2tp/l2tp_ppp.c:782 __sys_connect_file net/socket.c:1866 [inline] __sys_connect+0x388/0x410 net/socket.c:1883 __do_sys_connect net/socket.c:1893 [inline] __se_sys_connect net/socket.c:1890 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:1890 do_syscall_64+0x34/0x70 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 19: 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 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline] l2tp_session_dec_refcount+0xac/0x1b0 net/l2tp/l2tp_core.c:205 pppol2tp_session_destruct+0xaf/0xf0 net/l2tp/l2tp_ppp.c:419 __sk_destruct+0x59/0x620 net/core/sock.c:1813 sk_destruct net/core/sock.c:1858 [inline] __sk_free+0x36c/0x470 net/core/sock.c:1869 sk_free+0x51/0x80 net/core/sock.c:1880 sock_put include/net/sock.h:1850 [inline] pppol2tp_put_sk+0x77/0xb0 net/l2tp/l2tp_ppp.c:402 rcu_do_batch+0x597/0xc40 kernel/rcu/tree.c:2494 rcu_core+0x5ad/0xe40 kernel/rcu/tree.c:2735 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2748 __do_softirq+0x268/0x5bb kernel/softirq.c:309 Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd3/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2976 [inline] call_rcu+0x135/0x11f0 kernel/rcu/tree.c:3050 pppol2tp_release+0x20f/0x2d0 net/l2tp/l2tp_ppp.c:458 __sock_release net/socket.c:597 [inline] sock_close+0xdf/0x270 net/socket.c:1286 __fput+0x33d/0x7b0 fs/file_table.c:281 ____fput+0x15/0x20 fs/file_table.c:314 task_work_run+0x129/0x190 kernel/task_work.c:189 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop+0xbf/0xd0 kernel/entry/common.c:172 exit_to_user_mode_prepare kernel/entry/common.c:199 [inline] syscall_exit_to_user_mode+0xa2/0x1a0 kernel/entry/common.c:274 do_syscall_64+0x40/0x70 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb Second to last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd3/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 kvfree_call_rcu+0x136/0x650 kernel/rcu/tree.c:3535 drop_sysctl_table+0x311/0x450 fs/proc/proc_sysctl.c:1680 drop_sysctl_table+0x323/0x450 fs/proc/proc_sysctl.c:1683 unregister_sysctl_table+0x76/0x120 fs/proc/proc_sysctl.c:1718 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:127 neigh_sysctl_unregister+0x78/0x90 net/core/neighbour.c:3732 devinet_sysctl_unregister net/ipv4/devinet.c:2637 [inline] inetdev_destroy net/ipv4/devinet.c:324 [inline] inetdev_event+0x7c1/0x1040 net/ipv4/devinet.c:1599 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x8c/0xf0 kernel/notifier.c:410 call_netdevice_notifiers_info net/core/dev.c:2054 [inline] call_netdevice_notifiers_extack net/core/dev.c:2066 [inline] call_netdevice_notifiers net/core/dev.c:2080 [inline] unregister_netdevice_many+0xde7/0x17d0 net/core/dev.c:10747 default_device_exit_batch+0x38a/0x3f0 net/core/dev.c:11267 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 ffff88810f0e7c00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 8 bytes inside of 512-byte region [ffff88810f0e7c00, ffff88810f0e7e00) The buggy address belongs to the page: page:ffffea00043c3900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10f0e4 head:ffffea00043c3900 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 dead000000000100 dead000000000122 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 95, ts 3965303348, 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:5348 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] __kmalloc_track_caller+0x1f8/0x320 mm/slub.c:4536 __kmalloc_reserve net/core/skbuff.c:144 [inline] __alloc_skb+0xbc/0x510 net/core/skbuff.c:212 alloc_skb include/linux/skbuff.h:1126 [inline] alloc_uevent_skb+0x80/0x230 lib/kobject_uevent.c:290 uevent_net_broadcast_untagged lib/kobject_uevent.c:326 [inline] kobject_uevent_net_broadcast+0x311/0x590 lib/kobject_uevent.c:409 kobject_uevent_env+0x525/0x700 lib/kobject_uevent.c:608 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 page_owner free stack trace missing Memory state around the buggy address: ffff88810f0e7b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88810f0e7b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88810f0e7c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810f0e7c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810f0e7d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================