l2tp_core: tunl 2: sockfd_lookup(fd=5) returned -9 l2tp_core: tunl 2: sockfd_lookup(fd=5) returned -9 l2tp_core: tunl 2: sockfd_lookup(fd=5) returned -9 l2tp_core: tunl 2: sockfd_lookup(fd=5) returned -9 ================================================================== BUG: KASAN: use-after-free in ex_handler_refcount+0x164/0x1a0 arch/x86/mm/extable.c:49 Write of size 4 at addr ffff888093f12340 by task syz-executor.0/9861 CPU: 0 PID: 9861 Comm: syz-executor.0 Not tainted 4.14.174-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 ex_handler_refcount+0x164/0x1a0 arch/x86/mm/extable.c:49 fixup_exception+0x8a/0xc3 arch/x86/mm/extable.c:197 do_trap_no_signal arch/x86/kernel/traps.c:208 [inline] do_trap+0x72/0x230 arch/x86/kernel/traps.c:257 do_error_trap+0x132/0x2d0 arch/x86/kernel/traps.c:301 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963 RIP: 0010:inat_get_avx_attribute+0x623b/0x7956 RSP: 0018:ffff88808d9f7cd0 EFLAGS: 00010297 RAX: ffff888091340340 RBX: ffff88808ca4ca00 RCX: ffff888093f12340 RDX: 0000000000000000 RSI: ffff888091340bc0 RDI: ffff88808ca4cb98 RBP: ffff888093f122c0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808ca4ca00 R13: ffff888092d5a820 R14: ffffed10125ab504 R15: ffff888092d5a7e0 l2tp_tunnel_closeall+0x26f/0x370 net/l2tp/l2tp_core.c:1348 l2tp_udp_encap_destroy+0x8d/0xf0 net/l2tp/l2tp_core.c:1371 udpv6_destroy_sock+0xa6/0xd0 net/ipv6/udp.c:1444 sk_common_release+0x64/0x2f0 net/core/sock.c:2992 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 RIP: 0033:0x4163e1 RSP: 002b:00007fffcb05eaa0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 00000000004163e1 RDX: 0000000000000000 RSI: 0000000000000081 RDI: 0000000000000005 RBP: 0000000000000000 R08: 00000000007703e0 R09: 01ffffffffffffff R10: 00007fffcb05eb70 R11: 0000000000000293 R12: 000000000076bf00 R13: 00000000007703e8 R14: 0000000000000000 R15: 000000000076bf0c Allocated by task 9862: 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 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15b/0x7c0 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] sk_prot_alloc+0x164/0x290 net/core/sock.c:1467 sk_alloc+0x36/0xd60 net/core/sock.c:1521 pppol2tp_create+0x2d/0x1e0 net/l2tp/l2tp_ppp.c:534 pppox_create+0xf2/0x210 drivers/net/ppp/pppox.c:134 __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 9862: 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] kfree+0xcb/0x260 mm/slab.c:3815 sk_prot_free net/core/sock.c:1504 [inline] __sk_destruct+0x4f6/0x640 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] pppol2tp_release+0x247/0x2f0 net/l2tp/l2tp_ppp.c:501 __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 ffff888093f122c0 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff888093f122c0, ffff888093f12ac0) The buggy address belongs to the page: page:ffffea00024fc480 count:1 mapcount:0 mapping:ffff888093f122c0 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff888093f122c0 0000000000000000 0000000100000003 raw: ffffea00024cdfa0 ffffea000245c320 ffff88812fe56c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888093f12200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888093f12280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888093f12300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888093f12380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888093f12400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================