================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline] BUG: KASAN: use-after-free in sk_dst_get include/net/sock.h:1766 [inline] BUG: KASAN: use-after-free in pppol2tp_connect+0x15b4/0x17b0 net/l2tp/l2tp_ppp.c:749 Read of size 8 at addr ffff88808ded9368 by task syz-executor.2/6077 CPU: 1 PID: 6077 Comm: syz-executor.2 Not tainted 4.14.177-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393 __read_once_size include/linux/compiler.h:183 [inline] sk_dst_get include/net/sock.h:1766 [inline] pppol2tp_connect+0x15b4/0x17b0 net/l2tp/l2tp_ppp.c:749 SYSC_connect+0x1c6/0x250 net/socket.c:1655 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f4445ec1469 RSP: 002b:00007f44465b1db8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 000000000042d4e0 RCX: 00007f4445ec1469 RDX: 000000000000002e RSI: 0000000020000000 RDI: 0000000000000003 RBP: 00000000006abf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000008f R14: 000000000041582e R15: 00007f44465b25c0 Allocated by task 6073: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529 kmem_cache_alloc+0x127/0x770 mm/slab.c:3552 sk_prot_alloc+0x5f/0x290 net/core/sock.c:1461 sk_alloc+0x36/0xd60 net/core/sock.c:1521 inet6_create net/ipv6/af_inet6.c:183 [inline] inet6_create+0x2df/0xe20 net/ipv6/af_inet6.c:110 __sock_create+0x2f2/0x620 net/socket.c:1275 sock_create net/socket.c:1315 [inline] SYSC_socket net/socket.c:1345 [inline] SyS_socket+0xd2/0x170 net/socket.c:1325 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 5992: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kmem_cache_free+0x7c/0x2b0 mm/slab.c:3758 sk_prot_free net/core/sock.c:1502 [inline] __sk_destruct+0x3b1/0x640 net/core/sock.c:1581 sk_destruct+0x97/0xc0 net/core/sock.c:1596 __sk_free+0x4c/0x220 net/core/sock.c:1604 sk_free+0x2b/0x40 net/core/sock.c:1615 sock_put include/net/sock.h:1658 [inline] sk_common_release+0x1ec/0x2f0 net/core/sock.c:3022 inet_release+0xdf/0x1b0 net/ipv4/af_inet.c:425 inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:450 __sock_release+0xcd/0x2b0 net/socket.c:602 sock_close+0x15/0x20 net/socket.c:1139 __fput+0x25f/0x790 fs/file_table.c:210 task_work_run+0x113/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff88808ded9140 which belongs to the cache UDPv6 of size 1728 The buggy address is located 552 bytes inside of 1728-byte region [ffff88808ded9140, ffff88808ded9800) The buggy address belongs to the page: page:ffffea000237b640 count:1 mapcount:0 mapping:ffff88808ded9140 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff88808ded9140 0000000000000000 0000000100000002 raw: ffffea00025b04a0 ffffea000283a8e0 ffff888215c343c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808ded9200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808ded9280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808ded9300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808ded9380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808ded9400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================