==================================================================
BUG: KASAN: use-after-free in tcp_connect+0x2606/0x2fa0 net/ipv4/tcp_output.c:3413
Read of size 4 at addr ffff8801d08ef6a8 by task syz-executor.1/6356

CPU: 0 PID: 6356 Comm: syz-executor.1 Not tainted 4.9.141+ #1
 ffff8801ca8478c0 ffffffff81b42e79 ffffea0007423b80 ffff8801d08ef6a8
 0000000000000000 ffff8801d08ef6a8 ffff8801d1ea2860 ffff8801ca8478f8
 ffffffff815009b8 ffff8801d08ef6a8 0000000000000004 0000000000000000
Call Trace:
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff815009b8>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81500dc2>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81500dc2>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff814f3054>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 [<ffffffff825222a6>] tcp_connect+0x2606/0x2fa0 net/ipv4/tcp_output.c:3413
 [<ffffffff8273cf60>] tcp_v6_connect+0x1760/0x1ad0 net/ipv6/tcp_ipv6.c:298
 [<ffffffff82594680>] __inet_stream_connect+0x6e0/0xbf0 net/ipv4/af_inet.c:627
 [<ffffffff82594be5>] inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:691
 [<ffffffff822a3e28>] SYSC_connect net/socket.c:1575 [inline]
 [<ffffffff822a3e28>] SyS_connect+0x1b8/0x310 net/socket.c:1556
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Allocated by task 6358:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack mm/kasan/kasan.c:505 [inline]
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:609
 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:594
 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]
 kmem_cache_alloc+0xd5/0x2b0 mm/slub.c:2728
 kmem_cache_alloc_node include/linux/slab.h:364 [inline]
 __alloc_skb+0xe6/0x5b0 net/core/skbuff.c:219
 alloc_skb_fclone include/linux/skbuff.h:966 [inline]
 sk_stream_alloc_skb+0xa3/0x5d0 net/ipv4/tcp.c:828
 tcp_sendmsg+0xe72/0x2fd0 net/ipv4/tcp.c:1230
 inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770
 sock_sendmsg_nosec net/socket.c:648 [inline]
 sock_sendmsg+0xbb/0x110 net/socket.c:658
 ___sys_sendmsg+0x6fc/0x840 net/socket.c:1982
 __sys_sendmsg+0xd9/0x190 net/socket.c:2016
 SYSC_sendmsg net/socket.c:2027 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2023
 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Freed by task 6356:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack mm/kasan/kasan.c:505 [inline]
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_slab_free+0xac/0x190 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]
 kmem_cache_free+0xbe/0x310 mm/slub.c:2980
 kfree_skbmem+0x7c/0x100 net/core/skbuff.c:644
 __kfree_skb+0x1d/0x20 net/core/skbuff.c:685
 sk_wmem_free_skb include/net/sock.h:1358 [inline]
 tcp_write_queue_purge include/net/tcp.h:1530 [inline]
 tcp_connect_init net/ipv4/tcp_output.c:3253 [inline]
 tcp_connect+0xa74/0x2fa0 net/ipv4/tcp_output.c:3384
 tcp_v6_connect+0x1760/0x1ad0 net/ipv6/tcp_ipv6.c:298
 __inet_stream_connect+0x6e0/0xbf0 net/ipv4/af_inet.c:627
 inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:691
 SYSC_connect net/socket.c:1575 [inline]
 SyS_connect+0x1b8/0x310 net/socket.c:1556
 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the object at ffff8801d08ef680
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 40 bytes inside of
 456-byte region [ffff8801d08ef680, ffff8801d08ef848)
The buggy address belongs to the page:
page:ffffea0007423b80 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000004080(slab|head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d08ef580: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc
 ffff8801d08ef600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801d08ef680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff8801d08ef700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d08ef780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=770 sclass=netlink_route_socket pig=6369 comm=syz-executor.5