================================================================== BUG: KASAN: slab-use-after-free in l2tp_tunnel_del_work+0xe5/0x330 net/l2tp/l2tp_core.c:1334 Read of size 8 at addr ffff888024aea0b8 by task kworker/u8:4/63 CPU: 1 PID: 63 Comm: kworker/u8:4 Not tainted 6.10.0-rc5-syzkaller-01115-g30972a4ea092 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Workqueue: l2tp l2tp_tunnel_del_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 l2tp_tunnel_del_work+0xe5/0x330 net/l2tp/l2tp_core.c:1334 process_one_work kernel/workqueue.c:3248 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3329 worker_thread+0x86d/0xd50 kernel/workqueue.c:3409 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Allocated by task 11821: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slub.c:4123 [inline] __kmalloc_noprof+0x1f9/0x400 mm/slub.c:4136 kmalloc_noprof include/linux/slab.h:664 [inline] kzalloc_noprof include/linux/slab.h:778 [inline] l2tp_session_create+0x3b/0xc20 net/l2tp/l2tp_core.c:1675 pppol2tp_connect+0xca3/0x17a0 net/l2tp/l2tp_ppp.c:782 __sys_connect_file net/socket.c:2049 [inline] __sys_connect+0x2df/0x310 net/socket.c:2066 __do_sys_connect net/socket.c:2076 [inline] __se_sys_connect net/socket.c:2073 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2073 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5104: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2196 [inline] slab_free mm/slub.c:4438 [inline] kfree+0x149/0x360 mm/slub.c:4559 __sk_destruct+0x58/0x5f0 net/core/sock.c:2191 rcu_do_batch kernel/rcu/tree.c:2535 [inline] rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2809 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Last potentially related work creation: kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541 __call_rcu_common kernel/rcu/tree.c:3072 [inline] call_rcu+0x167/0xa70 kernel/rcu/tree.c:3176 pppol2tp_release+0x24b/0x350 net/l2tp/l2tp_ppp.c:457 __sock_release net/socket.c:659 [inline] sock_close+0xbc/0x240 net/socket.c:1421 __fput+0x406/0x8b0 fs/file_table.c:422 task_work_run+0x24f/0x310 kernel/task_work.c:180 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888024aea000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 184 bytes inside of freed 1024-byte region [ffff888024aea000, ffff888024aea400) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24ae8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffefff(slab) raw: 00fff00000000040 ffff888015041dc0 ffffea0000ad4c00 dead000000000002 raw: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000 head: 00fff00000000040 ffff888015041dc0 ffffea0000ad4c00 dead000000000002 head: 0000000000000000 0000000000100010 00000001ffffefff 0000000000000000 head: 00fff00000000003 ffffea000092ba01 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5103, tgid 5103 (syz-executor), ts 70894987023, free_ts 70893647280 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1473 prep_new_page mm/page_alloc.c:1481 [inline] get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3425 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4683 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x5f/0x120 mm/slub.c:2265 allocate_slab+0x5a/0x2f0 mm/slub.c:2428 new_slab mm/slub.c:2481 [inline] ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3667 __slab_alloc+0x58/0xa0 mm/slub.c:3757 __slab_alloc_node mm/slub.c:3810 [inline] slab_alloc_node mm/slub.c:3990 [inline] kmalloc_trace_noprof+0x1d5/0x2c0 mm/slub.c:4149 kmalloc_noprof include/linux/slab.h:660 [inline] kzalloc_noprof include/linux/slab.h:778 [inline] batadv_hardif_add_interface net/batman-adv/hard-interface.c:882 [inline] batadv_hard_if_event+0xe71/0x1620 net/batman-adv/hard-interface.c:970 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2032 [inline] call_netdevice_notifiers net/core/dev.c:2046 [inline] register_netdevice+0x167f/0x1b00 net/core/dev.c:10463 veth_newlink+0x84f/0xcd0 drivers/net/veth.c:1860 rtnl_newlink_create net/core/rtnetlink.c:3510 [inline] __rtnl_newlink net/core/rtnetlink.c:3730 [inline] rtnl_newlink+0x1591/0x20a0 net/core/rtnetlink.c:3743 rtnetlink_rcv_msg+0x89b/0x1180 net/core/rtnetlink.c:6641 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357 page last free pid 5103 tgid 5103 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1093 [inline] free_unref_page+0xd22/0xea0 mm/page_alloc.c:2588 discard_slab mm/slub.c:2527 [inline] __put_partials+0xeb/0x130 mm/slub.c:2995 put_cpu_partial+0x17c/0x250 mm/slub.c:3070 __slab_free+0x2ea/0x3d0 mm/slub.c:4308 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3940 [inline] slab_alloc_node mm/slub.c:4002 [inline] kmalloc_trace_noprof+0x132/0x2c0 mm/slub.c:4149 kmalloc_noprof include/linux/slab.h:660 [inline] kzalloc_noprof include/linux/slab.h:778 [inline] ref_tracker_alloc+0x14b/0x490 lib/ref_tracker.c:203 register_netdevice+0x150b/0x1b00 net/core/dev.c:10450 veth_newlink+0x84f/0xcd0 drivers/net/veth.c:1860 rtnl_newlink_create net/core/rtnetlink.c:3510 [inline] __rtnl_newlink net/core/rtnetlink.c:3730 [inline] rtnl_newlink+0x1591/0x20a0 net/core/rtnetlink.c:3743 rtnetlink_rcv_msg+0x89b/0x1180 net/core/rtnetlink.c:6641 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901 Memory state around the buggy address: ffff888024ae9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888024aea000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888024aea080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888024aea100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888024aea180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================