protocol 8847 is buggy, dev sit0 ================================================================== BUG: KASAN: use-after-free in skb_is_gso include/linux/skbuff.h:4035 [inline] BUG: KASAN: use-after-free in iptunnel_handle_offloads+0x62b/0x710 net/ipv4/ip_tunnel_core.c:170 Read of size 2 at addr ffff8801c83b8b84 by task syz-executor7/10633 CPU: 1 PID: 10633 Comm: syz-executor7 Not tainted 4.17.0-rc4+ #46 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 FAT-fs (loop3): Directory bread(block 112) failed print_address_description+0x6c/0x20b mm/kasan/report.c:256 FAT-fs (loop3): Directory bread(block 113) failed kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+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:4035 [inline] iptunnel_handle_offloads+0x62b/0x710 net/ipv4/ip_tunnel_core.c:170 FAT-fs (loop3): Directory bread(block 114) failed sit_tunnel_xmit__+0x2a/0x160 net/ipv6/sit.c:1008 sit_tunnel_xmit+0x1275/0x30b0 net/ipv6/sit.c:1033 FAT-fs (loop3): Directory bread(block 112) failed FAT-fs (loop3): Directory bread(block 113) failed __netdev_start_xmit include/linux/netdevice.h:4087 [inline] netdev_start_xmit include/linux/netdevice.h:4096 [inline] xmit_one net/core/dev.c:3053 [inline] dev_hard_start_xmit+0x264/0xc10 net/core/dev.c:3069 FAT-fs (loop3): Directory bread(block 114) failed __dev_queue_xmit+0x2724/0x34c0 net/core/dev.c:3584 FAT-fs (loop3): Directory bread(block 112) failed FAT-fs (loop3): Directory bread(block 113) failed FAT-fs (loop3): Directory bread(block 114) failed dev_queue_xmit+0x17/0x20 net/core/dev.c:3617 packet_snd net/packet/af_packet.c:2951 [inline] packet_sendmsg+0x40f8/0x6070 net/packet/af_packet.c:2976 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 __sys_sendto+0x3d7/0x670 net/socket.c:1789 __do_sys_sendto net/socket.c:1801 [inline] __se_sys_sendto net/socket.c:1797 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455979 RSP: 002b:00007fa17f3afc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fa17f3b06d4 RCX: 0000000000455979 RDX: 0000000000000000 RSI: 0000000020003fd9 RDI: 0000000000000015 RBP: 000000000072bea0 R08: 0000000020008000 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000005ac R14: 00000000006fc8c0 R15: 0000000000000000 Allocated by task 10633: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3696 __kmalloc_reserve.isra.38+0x3a/0xe0 net/core/skbuff.c:137 __alloc_skb+0x14d/0x780 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:987 [inline] alloc_skb_with_frags+0x137/0x760 net/core/skbuff.c:5249 sock_alloc_send_pskb+0x87a/0xae0 net/core/sock.c:2088 packet_alloc_skb net/packet/af_packet.c:2810 [inline] packet_snd net/packet/af_packet.c:2901 [inline] packet_sendmsg+0x1b98/0x6070 net/packet/af_packet.c:2976 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 __sys_sendto+0x3d7/0x670 net/socket.c:1789 __do_sys_sendto net/socket.c:1801 [inline] __se_sys_sendto net/socket.c:1797 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 10633: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 skb_free_head+0x99/0xc0 net/core/skbuff.c:550 skb_release_data+0x690/0x860 net/core/skbuff.c:570 skb_release_all+0x4a/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] consume_skb+0x18b/0x550 net/core/skbuff.c:701 packet_rcv+0x16a/0x1810 net/packet/af_packet.c:2169 dev_queue_xmit_nit+0x891/0xb90 net/core/dev.c:2018 xmit_one net/core/dev.c:3049 [inline] dev_hard_start_xmit+0x16b/0xc10 net/core/dev.c:3069 __dev_queue_xmit+0x2724/0x34c0 net/core/dev.c:3584 dev_queue_xmit+0x17/0x20 net/core/dev.c:3617 packet_snd net/packet/af_packet.c:2951 [inline] packet_sendmsg+0x40f8/0x6070 net/packet/af_packet.c:2976 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:639 __sys_sendto+0x3d7/0x670 net/socket.c:1789 __do_sys_sendto net/socket.c:1801 [inline] __se_sys_sendto net/socket.c:1797 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801c83b8ac0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 196 bytes inside of 512-byte region [ffff8801c83b8ac0, ffff8801c83b8cc0) The buggy address belongs to the page: page:ffffea000720ee00 count:1 mapcount:0 mapping:ffff8801c83b80c0 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801c83b80c0 0000000000000000 0000000100000006 raw: ffffea000722dca0 ffffea0006f59c60 ffff8801da800940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c83b8a80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8801c83b8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801c83b8b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801c83b8c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c83b8c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================