netlink: 4 bytes leftover after parsing attributes in process `syz-executor4'. EXT4-fs (sda1): re-mounted. Opts: protocol 0800 is buggy, dev sit0 ================================================================== BUG: KASAN: use-after-free in skb_is_gso include/linux/skbuff.h:3766 [inline] BUG: KASAN: use-after-free in iptunnel_handle_offloads+0x462/0x520 net/ipv4/ip_tunnel_core.c:168 Read of size 2 at addr ffff8801d51cf4c2 by task syz-executor5/18292 CPU: 0 PID: 18292 Comm: syz-executor5 Not tainted 4.9.99-gc462abb #20 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801c12cf2e0 ffffffff81eb0f09 ffffea0007547380 ffff8801d51cf4c2 0000000000000000 ffff8801d51cf4c2 ffff8801d01e0988 ffff8801c12cf318 ffffffff815652eb ffff8801d51cf4c2 0000000000000002 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_address_description+0x6c/0x234 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412 [] __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:431 [] skb_is_gso include/linux/skbuff.h:3766 [inline] [] iptunnel_handle_offloads+0x462/0x520 net/ipv4/ip_tunnel_core.c:168 [] sit_tunnel_xmit__ net/ipv6/sit.c:997 [inline] [] sit_tunnel_xmit+0x15b/0x2590 net/ipv6/sit.c:1015 [] __netdev_start_xmit include/linux/netdevice.h:4062 [inline] [] netdev_start_xmit include/linux/netdevice.h:4071 [inline] [] xmit_one net/core/dev.c:2955 [inline] [] dev_hard_start_xmit+0x197/0x8b0 net/core/dev.c:2971 [] __dev_queue_xmit+0x19a5/0x2080 net/core/dev.c:3451 [] dev_queue_xmit+0x17/0x20 net/core/dev.c:3484 [] packet_snd net/packet/af_packet.c:2960 [inline] [] packet_sendmsg+0x1eff/0x4470 net/packet/af_packet.c:2985 [] sock_sendmsg_nosec net/socket.c:635 [inline] [] sock_sendmsg+0xcc/0x110 net/socket.c:645 [] ___sys_sendmsg+0x47a/0x840 net/socket.c:1969 [] __sys_sendmmsg+0x161/0x3d0 net/socket.c:2059 [] SYSC_sendmmsg net/socket.c:2090 [inline] [] SyS_sendmmsg+0x35/0x60 net/socket.c:2085 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 18292: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:609 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:547 slab_post_alloc_hook mm/slab.h:417 [inline] slab_alloc_node mm/slub.c:2715 [inline] slab_alloc mm/slub.c:2723 [inline] __kmalloc_track_caller+0xdc/0x2b0 mm/slub.c:4232 __kmalloc_reserve.isra.37+0x33/0xc0 net/core/skbuff.c:138 __alloc_skb+0x11a/0x600 net/core/skbuff.c:231 alloc_skb include/linux/skbuff.h:919 [inline] alloc_skb_with_frags+0xaf/0x520 net/core/skbuff.c:4678 sock_alloc_send_pskb+0x5a9/0x750 net/core/sock.c:1893 packet_alloc_skb net/packet/af_packet.c:2817 [inline] packet_snd net/packet/af_packet.c:2908 [inline] packet_sendmsg+0x1581/0x4470 net/packet/af_packet.c:2985 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xcc/0x110 net/socket.c:645 ___sys_sendmsg+0x47a/0x840 net/socket.c:1969 __sys_sendmmsg+0x161/0x3d0 net/socket.c:2059 SYSC_sendmmsg net/socket.c:2090 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2085 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 18292: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:505 set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kfree+0xfb/0x310 mm/slub.c:3878 skb_free_head+0x8b/0xb0 net/core/skbuff.c:580 skb_release_data+0x329/0x400 net/core/skbuff.c:611 skb_release_all+0x4a/0x60 net/core/skbuff.c:670 __kfree_skb net/core/skbuff.c:684 [inline] consume_skb+0xc6/0x340 net/core/skbuff.c:757 packet_rcv+0xe2/0x11e0 net/packet/af_packet.c:2140 dev_queue_xmit_nit+0x5d7/0x820 net/core/dev.c:1928 xmit_one net/core/dev.c:2951 [inline] dev_hard_start_xmit+0xa6/0x8b0 net/core/dev.c:2971 __dev_queue_xmit+0x19a5/0x2080 net/core/dev.c:3451 dev_queue_xmit+0x17/0x20 net/core/dev.c:3484 packet_snd net/packet/af_packet.c:2960 [inline] packet_sendmsg+0x1eff/0x4470 net/packet/af_packet.c:2985 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xcc/0x110 net/socket.c:645 ___sys_sendmsg+0x47a/0x840 net/socket.c:1969 __sys_sendmmsg+0x161/0x3d0 net/socket.c:2059 SYSC_sendmmsg net/socket.c:2090 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2085 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801d51cf400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 194 bytes inside of 512-byte region [ffff8801d51cf400, ffff8801d51cf600) The buggy address belongs to the page: page:ffffea0007547380 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x8000000000004080(slab|head) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d51cf380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d51cf400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801d51cf480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d51cf500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d51cf580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================