RBP: 0000000020000080 R08: 00000000000000fc R09: 0000000000000000
R10: 000000000000002e R11: 0000000000000293 R12: 0000000000000013
R13: 0000000000000653 R14: 00000000006fc868 R15: 0000000000000003
protocol 0000 is buggy, dev sit0
==================================================================
BUG: KASAN: use-after-free in copyout+0x7d/0xb0 lib/iov_iter.c:136
Read of size 1 at addr ffff8801ca1ba5c0 by task syz-executor0/12448

CPU: 1 PID: 12448 Comm: syz-executor0 Not tainted 4.16.0+ #14
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+0x1a7/0x27d lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23c/0x360 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 copyout+0x7d/0xb0 lib/iov_iter.c:136
 _copy_to_iter+0x262/0x13a0 lib/iov_iter.c:565
 copy_to_iter include/linux/uio.h:106 [inline]
 skb_copy_datagram_iter+0x1c2/0xac0 net/core/datagram.c:431
 skb_copy_datagram_msg include/linux/skbuff.h:3260 [inline]
 packet_recvmsg+0x2b9/0x17a0 net/packet/af_packet.c:3341
 sock_recvmsg_nosec net/socket.c:802 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:809
 sock_read_iter+0x35b/0x560 net/socket.c:886
 call_read_iter include/linux/fs.h:1776 [inline]
 new_sync_read fs/read_write.c:406 [inline]
 __vfs_read+0x6a7/0xa00 fs/read_write.c:418
 vfs_read+0x11e/0x350 fs/read_write.c:452
 ksys_read+0xef/0x220 fs/read_write.c:578
 SYSC_read fs/read_write.c:588 [inline]
 SyS_read+0x24/0x30 fs/read_write.c:586
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4552d9
RSP: 002b:00007fca13285c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fca132866d4 RCX: 00000000004552d9
RDX: 0000000000000057 RSI: 00000000200000c0 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000486 R14: 00000000006f9d30 R15: 0000000000000000

Allocated by task 12489:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
 __do_kmalloc_node mm/slab.c:3670 [inline]
 __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3684
 __kmalloc_reserve.isra.39+0x41/0xd0 net/core/skbuff.c:137
 __alloc_skb+0x12a/0x760 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:987 [inline]
 alloc_skb_with_frags+0x10d/0x750 net/core/skbuff.c:5248
 sock_alloc_send_pskb+0x7b3/0x9e0 net/core/sock.c:2088
 packet_alloc_skb net/packet/af_packet.c:2803 [inline]
 packet_snd net/packet/af_packet.c:2894 [inline]
 packet_sendmsg+0x1ed7/0x6020 net/packet/af_packet.c:2969
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:639
 __sys_sendto+0x365/0x5a0 net/socket.c:1789
 SYSC_sendto net/socket.c:1801 [inline]
 SyS_sendto+0x40/0x60 net/socket.c:1797
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 12489:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3486 [inline]
 kfree+0xd9/0x260 mm/slab.c:3801
 skb_free_head+0x74/0xb0 net/core/skbuff.c:550
 skb_release_data+0x5c1/0x790 net/core/skbuff.c:570
 skb_release_all+0x4a/0x60 net/core/skbuff.c:627
 __kfree_skb net/core/skbuff.c:641 [inline]
 kfree_skb+0x16b/0x4c0 net/core/skbuff.c:659
 sit_tunnel_xmit+0x157/0x2db0 net/ipv6/sit.c:1042
 __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+0x24e/0xac0 net/core/dev.c:3069
 __dev_queue_xmit+0x26cf/0x2fd0 net/core/dev.c:3584
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3617
 packet_snd net/packet/af_packet.c:2944 [inline]
 packet_sendmsg+0x3ad9/0x6020 net/packet/af_packet.c:2969
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:639
 __sys_sendto+0x365/0x5a0 net/socket.c:1789
 SYSC_sendto net/socket.c:1801 [inline]
 SyS_sendto+0x40/0x60 net/socket.c:1797
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8801ca1ba540
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 128 bytes inside of
 512-byte region [ffff8801ca1ba540, ffff8801ca1ba740)
The buggy address belongs to the page:
page:ffffea0007286e80 count:1 mapcount:0 mapping:ffff8801ca1ba040 index:0xffff8801ca1ba2c0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801ca1ba040 ffff8801ca1ba2c0 0000000100000004
raw: ffffea0006f81aa0 ffffea0006c650a0 ffff8801dac00940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ca1ba480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801ca1ba500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8801ca1ba580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8801ca1ba600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801ca1ba680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================