================================================================== 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 ffff88811f4d5408 by task kworker/u4:5/513 CPU: 1 PID: 513 Comm: kworker/u4:5 Not tainted 5.15.167-syzkaller-00002-g3bfe08931bff #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:88 [inline] dump_stack_lvl+0x151/0x1c0 lib/dump_stack.c:106 print_address_description+0x87/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0x179/0x1c0 mm/kasan/report.c:444 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+0x6bb/0xc10 kernel/workqueue.c:2325 worker_thread+0xad5/0x12a0 kernel/workqueue.c:2472 kthread+0x421/0x510 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 7084: 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:433 [inline] ____kasan_kmalloc+0xdb/0x110 mm/kasan/common.c:512 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:521 kasan_kmalloc include/linux/kasan.h:227 [inline] __kmalloc+0x13a/0x270 mm/slub.c:4427 kmalloc include/linux/slab.h:608 [inline] kzalloc include/linux/slab.h:733 [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:1918 [inline] __sys_connect+0x38b/0x410 net/socket.c:1935 __do_sys_connect net/socket.c:1945 [inline] __se_sys_connect net/socket.c:1942 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:1942 x64_sys_call+0x14e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 25: 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+0x126/0x160 mm/kasan/common.c:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0xbd/0x190 mm/slub.c:1749 slab_free mm/slub.c:3519 [inline] kfree+0xc8/0x220 mm/slub.c:4579 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline] l2tp_session_dec_refcount+0xa9/0x1b0 net/l2tp/l2tp_core.c:205 pppol2tp_session_destruct+0xaf/0xf0 net/l2tp/l2tp_ppp.c:419 __sk_destruct+0x56/0x5b0 net/core/sock.c:1961 sk_destruct net/core/sock.c:2006 [inline] __sk_free+0x36c/0x470 net/core/sock.c:2017 sk_free+0x51/0x80 net/core/sock.c:2028 sock_put include/net/sock.h:1921 [inline] pppol2tp_put_sk+0x77/0xb0 net/l2tp/l2tp_ppp.c:402 rcu_do_batch+0x57a/0xc10 kernel/rcu/tree.c:2523 rcu_core+0x517/0x1020 kernel/rcu/tree.c:2763 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776 handle_softirqs+0x25e/0x5c0 kernel/softirq.c:565 run_ksoftirqd+0x28/0x40 kernel/softirq.c:941 smpboot_thread_fn+0x466/0x8d0 kernel/smpboot.c:164 kthread+0x421/0x510 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Last potentially related work creation: kasan_save_stack+0x3b/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd3/0xf0 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu_common kernel/rcu/tree.c:3007 [inline] call_rcu+0x123/0x10b0 kernel/rcu/tree.c:3125 pppol2tp_release+0x20f/0x2d0 net/l2tp/l2tp_ppp.c:458 __sock_release net/socket.c:649 [inline] sock_close+0xdf/0x270 net/socket.c:1336 __fput+0x228/0x8c0 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:308 task_work_run+0x129/0x190 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0xc4/0xe0 kernel/entry/common.c:181 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x26/0x160 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff88811f4d5400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 8 bytes inside of 512-byte region [ffff88811f4d5400, ffff88811f4d5600) The buggy address belongs to the page: page:ffffea00047d3500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f4d4 head:ffffea00047d3500 order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 ffffea00047d3400 0000000700000007 ffff888100042f00 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), pid 6816, ts 408413495683, free_ts 406818245654 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1a3/0x1b0 mm/page_alloc.c:2605 prep_new_page+0x1b/0x110 mm/page_alloc.c:2611 get_page_from_freelist+0x3550/0x35d0 mm/page_alloc.c:4485 __alloc_pages+0x27e/0x8f0 mm/page_alloc.c:5779 allocate_slab mm/slub.c:1932 [inline] new_slab+0x9a/0x4e0 mm/slub.c:1995 ___slab_alloc+0x39e/0x830 mm/slub.c:3028 __slab_alloc+0x4a/0x90 mm/slub.c:3115 slab_alloc_node mm/slub.c:3206 [inline] slab_alloc mm/slub.c:3248 [inline] __kmalloc_track_caller+0x16c/0x260 mm/slub.c:4945 kmalloc_reserve net/core/skbuff.c:357 [inline] __alloc_skb+0x10c/0x550 net/core/skbuff.c:428 alloc_skb include/linux/skbuff.h:1183 [inline] nlmsg_new include/net/netlink.h:953 [inline] netlink_ack+0x33c/0xb10 net/netlink/af_netlink.c:2442 netlink_rcv_skb+0x24c/0x410 net/netlink/af_netlink.c:2513 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5636 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x8df/0xac0 net/netlink/af_netlink.c:1356 netlink_sendmsg+0xa0a/0xd20 net/netlink/af_netlink.c:1924 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] __sys_sendto+0x564/0x720 net/socket.c:2058 __do_sys_sendto net/socket.c:2070 [inline] __se_sys_sendto net/socket.c:2066 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:2066 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1472 [inline] free_pcp_prepare mm/page_alloc.c:1544 [inline] free_unref_page_prepare+0x7c8/0x7d0 mm/page_alloc.c:3534 free_unref_page+0xe8/0x750 mm/page_alloc.c:3616 free_the_page mm/page_alloc.c:805 [inline] __free_pages+0x61/0xf0 mm/page_alloc.c:5855 __free_slab+0xec/0x1d0 mm/slub.c:2020 free_slab mm/slub.c:2035 [inline] discard_slab mm/slub.c:2041 [inline] __unfreeze_partials+0x165/0x1a0 mm/slub.c:2527 put_cpu_partial+0xc4/0x120 mm/slub.c:2607 __slab_free+0x1c8/0x290 mm/slub.c:3388 do_slab_free mm/slub.c:3507 [inline] ___cache_free+0x109/0x120 mm/slub.c:3526 qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157 qlist_free_all+0x44/0xb0 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x15a/0x180 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:443 kasan_slab_alloc include/linux/kasan.h:217 [inline] slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:550 slab_alloc_node mm/slub.c:3240 [inline] slab_alloc mm/slub.c:3248 [inline] kmem_cache_alloc+0xf5/0x200 mm/slub.c:3253 vm_area_dup+0x26/0x230 kernel/fork.c:367 __split_vma+0xc1/0x470 mm/mmap.c:2752 Memory state around the buggy address: ffff88811f4d5300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88811f4d5380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88811f4d5400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88811f4d5480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811f4d5500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================